Used in the treatment of various cancers by enhancing the body's immune response against tumor cells. It works by blocking the PD-1 receptor on T-cells, preventing cancer cells from evading immune detection. Commonly applied in melanoma, non-small cell lung cancer, head and neck cancers, classical Hodgkin lymphoma, and other solid tumors. Administered intravenously, it helps improve survival rates and can lead to durable responses in some patients. Often used when tumors express high levels of PD-L1 or in cases with specific genetic markers. Also being studied in combination with other immunotherapies, chemotherapy, or radiation to increase effectiveness.