Programmed death-ligand 1 (PD-L1) is a cell surface receptor used by a variety of cancer cells to evade immune-mediated apoptosis of the malignant cells, and PD-L1 inhibitors such as Pembrolizumab have been approved for treatment of multiple cancer types including melanoma, and lung and head/neck carcinomas. This evidence concerns the gene CD274 and head and neck carcinoma.