CD274 and melanoma: Immunotherapy has made astounding advances in the treatment of cancer.[1] Programmed death protein-1/ligand-1 (PD-1/PD-L1) inhibitors, representative immune checkpoint inhibitors used in immunotherapy,[1,2] have been approved to treat a variety of tumors, such as non-small cell lung cancer (NSCLC), urothelial cancer, melanoma, head and neck squamous cell cancer, lymphoma.[3]