Over the past decade, monoclonal antibody-based immune checkpoint inhibitors targeting programmed death-1 (PD-1) and its ligand, programmed death-ligand 1 (PD-L1), have been developed and approved by the U.S. Food and Drug Administration (FDA) for the treatment of solid tumors such as non-small cell lung cancer, melanoma, urothelial carcinoma, and head and neck squamous cell carcinoma [1–5]. Here, CD274 is linked to melanoma.