Used in cancer immunotherapy to enhance the body's immune response against tumor cells by blocking the interaction between PD-1 and PD-L1, which suppresses T-cell activity. This inhibition allows T-cells to recognize and destroy cancer cells more effectively. Commonly applied in treating various malignancies such as melanoma, non-small cell lung cancer, and renal cell carcinoma. Enables longer progression-free survival and improved clinical outcomes in responsive patients. Often used in combination with other immunotherapies or chemotherapies to boost efficacy.