CD274 and skin squamous cell carcinoma: The treatment paradigm for recurrent or metastatic CSCC not amenable to surgery or radiation therapy has been transformed with immune checkpoint blockade (ICB) specifically targeting the Programmed Death-1 (PD-1) receptor and ligand (PD-L1) axis, which achieves an objective response rate of ~50%, with durable control and rapid improvement of quality of life [10,11,12,13,14].