CD274 and melanoma: Indeed, recent studies revealed that immune checkpoint blockades with monoclonal antibodies (mAbs) that target the programmed cell death receptor 1 (PD-1) and its ligand (PD-L1) have been widely used in treating human cancers and showing in an enhanced host anti-tumor immunity and increase survival rates in a variety of malignancies including melanoma (8), renal cell carcinoma (9), and non-small cell lung cancer (10).