Used in cancer immunotherapy to enhance the body's immune response against tumor cells by blocking the interaction between PD-1 and PD-L1, thereby preventing immune evasion by cancer cells. This inhibition allows T-cells to remain active and effectively target malignant cells. Commonly applied in treating various solid tumors, including non-small cell lung cancer, melanoma, and renal cell carcinoma. Often utilized in combination with other immunotherapies or chemotherapies to improve clinical outcomes.