Immunotherapy is now approved to treat more than 20 types of cancer, spanning common solid tumors like lung cancer, melanoma, and bladder cancer to blood cancers like lymphoma, leukemia, and multiple myeloma. The list continues to grow, with new approvals expanding to ovarian cancer, Hodgkin lymphoma, and other indications in recent years. Not every patient with these cancers will qualify, but the range of options has widened dramatically since the first modern immunotherapy drugs arrived around 2011.
How Immunotherapy Works
Cancer cells survive partly by hiding from the immune system. They exploit natural “off switches” on immune cells called T cells. These switches, known as checkpoint proteins, normally prevent T cells from attacking healthy tissue. But many tumors produce high levels of proteins that flip those switches, essentially telling T cells to stand down. Immunotherapy drugs block that signal, freeing T cells to recognize and kill cancer cells they were previously ignoring.
Other forms of immunotherapy take a more direct approach. Some involve engineering a patient’s own immune cells in a lab to better target cancer. Others use vaccines or viruses to train the immune system to attack tumors. The type of immunotherapy recommended depends on the cancer, its stage, and specific biological markers on the tumor.
Cancers Treated With Checkpoint Inhibitors
Checkpoint inhibitors are the most widely used form of immunotherapy. They block the proteins (PD-1, PD-L1, or CTLA-4) that cancers use to shut down immune responses. The FDA has approved checkpoint inhibitors for a long and growing list of cancers, including:
- Lung cancer (non-small cell and some small cell)
- Melanoma
- Bladder (urothelial) cancer
- Kidney cancer
- Head and neck cancers
- Liver cancer
- Stomach and esophageal cancers
- Colorectal cancer (specific subtypes)
- Cervical cancer
- Hodgkin lymphoma
- Ovarian, fallopian tube, and peritoneal cancers
- Triple-negative breast cancer
Pembrolizumab (Keytruda) and nivolumab (Opdivo) are the two checkpoint inhibitors with the broadest range of approved uses. Pembrolizumab alone now covers more than 15 different cancer types. In some cases, these drugs are used on their own; in others, they’re combined with chemotherapy to improve results.
One especially important approval applies across cancer types rather than to a single organ. The FDA has approved pembrolizumab for any solid tumor that tests positive for a feature called microsatellite instability-high (MSI-H) or mismatch repair deficiency. This was the first time the agency approved a cancer drug based on a tumor’s genetic characteristics rather than where it originated in the body. It means that even cancers without a specific immunotherapy approval may qualify if they carry this marker.
Blood Cancers Treated With CAR T-Cell Therapy
CAR T-cell therapy is a more intensive form of immunotherapy. Doctors collect a patient’s T cells, genetically modify them in a lab to better recognize cancer, then infuse them back into the patient. The process takes several weeks and typically requires a hospital stay, but it can produce durable remissions in cancers that have stopped responding to other treatments.
The FDA has approved seven CAR T-cell products for blood cancers. The specific types they treat include:
- Large B-cell lymphoma (including diffuse large B-cell lymphoma)
- Follicular lymphoma
- Mantle cell lymphoma
- B-cell acute lymphoblastic leukemia (ALL) in both children and adults
- Chronic lymphocytic leukemia
- Multiple myeloma
CAR T-cell therapy is generally reserved for patients whose cancer has returned after earlier treatment or hasn’t responded to standard options. For multiple myeloma, for instance, two approved CAR T products target patients who have already been through at least one prior line of therapy. These are not first-line treatments for most people, but they offer a path forward when conventional chemotherapy has run its course.
Cancers Treated With Vaccines and Other Approaches
Three therapeutic cancer vaccines have FDA approval, each for a different cancer type:
- Early-stage bladder cancer: BCG, a bacterium-based treatment injected directly into the bladder, has been used since 1990. It stimulates a local immune response against cancer cells lining the bladder wall.
- Advanced prostate cancer: Sipuleucel-T (Provenge) is approved for prostate cancer that no longer responds to hormone therapy. It uses a patient’s own immune cells, processed in a lab to target prostate cancer proteins, then returned through infusion.
- Melanoma: T-VEC (Imlygic), approved in 2015, is a modified virus injected directly into melanoma tumors that can’t be surgically removed. The virus replicates inside cancer cells, killing them and triggering a broader immune response.
Bispecific antibodies represent a newer category. These engineered proteins grab onto both a T cell and a cancer cell at the same time, physically bridging them together so the immune cell can attack. The FDA recently approved teclistamab for relapsed or refractory multiple myeloma in combination with other drugs, and several other bispecific antibodies are approved for blood cancers.
Biomarkers That Determine Eligibility
Having a cancer type on the approved list doesn’t automatically mean immunotherapy will be offered. For many cancers, doctors test the tumor for specific biological markers to predict whether the treatment is likely to work.
PD-L1 expression is the most common marker tested. Tumors that produce more of this protein are generally more responsive to checkpoint inhibitors. In non-small cell lung cancer, patients whose tumors express PD-L1 on 50% or more of their cells see significantly better outcomes with pembrolizumab compared to chemotherapy alone. But the relationship isn’t absolute. Across multiple cancer types, about 15% of patients with PD-L1-negative tumors still respond to checkpoint inhibitors, compared to about 48% of those with PD-L1-positive tumors.
MSI-H/dMMR status is another key marker. Tumors with these features have a harder time repairing their own DNA, which creates more mutations and more abnormal proteins for the immune system to recognize. This is why these cancers tend to respond well to immunotherapy regardless of where they are in the body. MSI-H is most commonly found in colorectal, endometrial, and gastric cancers, though it can appear in almost any tumor type.
Tumor mutational burden (TMB), which measures the total number of mutations in a cancer’s DNA, is a third factor. Cancers with high TMB carry more abnormal proteins on their surface, making them more visible to the immune system. The FDA has approved pembrolizumab for any solid tumor with high TMB that has progressed after prior treatment.
Where Immunotherapy Has Changed Survival
Metastatic melanoma offers the starkest example of immunotherapy’s impact. Before checkpoint inhibitors, the five-year survival rate for melanoma that had spread to distant organs was in the single digits. Current data shows a five-year relative survival rate of 35% for distant-stage melanoma, and that figure is based on patients diagnosed between 2015 and 2021. People diagnosed more recently may do even better as treatment combinations improve and newer drugs reach the market.
In non-small cell lung cancer, checkpoint inhibitors have become a standard part of first-line treatment for many patients, particularly those with high PD-L1 expression. Bladder cancer, kidney cancer, and head and neck cancers have also seen meaningful survival improvements with immunotherapy, often in patients who previously had few effective options after chemotherapy failed.
Results remain uneven across cancer types. Pancreatic cancer, most brain cancers, and prostate cancer (outside the vaccine approval) have proven far more resistant to checkpoint inhibitors. These tumors tend to create environments that suppress immune activity or have low mutation rates, making them harder for the immune system to detect even with help. The presence of specific biomarkers matters more than the cancer’s name on the label, which is why testing before treatment is a critical step.