CD274 and neoplasm: As the main ligand for PD-1, PD-L1 induces a coinhibitory signal in activated T-cells and promotes T-cell apoptosis, anergy, and functional exhaustion.[6,7] There is evidence that tumor cells can express PD-L1 on the cell membrane by activated T-cells.[8,9] This has been investigated in metastatic renal cell carcinoma (RCC), suggesting that primary RCC tumors with PD-L1 positivity—either on tumor cell membranes or inflammatory cells—will have a better response to PD-1/PD-L1-targeting therapies.[10]