Used in the treatment of advanced cutaneous squamous cell carcinoma (CSCC) and basal cell carcinoma (BCC) in patients who are not candidates for curative surgery or radiation. It is also approved for first-line treatment of metastatic or locally advanced non-small cell lung cancer (NSCLC) with high PD-L1 expression (≥50%) and no EGFR, ALK, or ROS1 alterations. As a programmed death receptor-1 (PD-1) inhibitor, it works by enhancing the body's immune response against cancer cells. Administered intravenously, it helps improve survival and reduce tumor size in eligible patients.