PDCD1 and melanoma: Immune checkpoint inhibitors such as anti-PD-1 (nivolumab, pembrolizumab, cemiplimab), anti-PD-L1 (durvalumab, atezolizumab) and anti-CTLA-4 (ipilimumab [IPI]) were shown to significantly improve survival in melanoma and other cancers, including non-melanoma skin cancers (merkel cell carcinoma and cutaneous squamous cell carcinoma), lung cancer, renal cell carcinoma, head and neck cancer, and hepatocellular carcinoma.