A drug that binds to the protein PD-1 to help immune cells kill cancer cells better and is used to treat many different types of cancer. These include cancers that express the protein PD-L1 or that have certain mutations (changes) in genes involved in DNA repair. Opdivo is used alone or with other drugs to treat certain types of colorectal cancer, non-small cell lung cancer, renal cell carcinoma, melanoma, hepatocellular carcinoma, squamous cell carcinoma (SCC) of the esophagus, small cell lung cancer, SCC of the head and neck, classic Hodgkin lymphoma, and urothelial carcinoma. It is also being studied in the treatment of other types of cancer. Opdivo may block PD-1 and help the immune system kill cancer cells. It is a type of monoclonal antibody and a type of immune checkpoint inhibitor. Also called nivolumab.