Used in the treatment of various cancers, particularly non-small cell lung cancer and classical Hodgkin's lymphoma, by blocking the PD-1 receptor on T-cells. This inhibition enhances the immune system’s ability to detect and attack tumor cells. It is administered intravenously and often used when other treatments have failed or in combination with chemotherapy. Shows significant clinical response in patients with high PD-L1 expression. Also being studied in other solid tumors and hematologic malignancies.