Keytruda (pembrolizumab) is an immunotherapy medicine used to treat many types of cancer, including non-small cell lung cancer, melanoma, triple-negative breast cancer, urothelial cancer, renal cell carcinoma, head and neck squamous cell carcinoma, cervical cancer, and others. It belongs to a class of drugs called PD-1 inhibitors, also known as immune checkpoint inhibitors. price of keytruda