CD274 and urothelial carcinoma: To date, a number of antibodies targeting PD-L1 are in clinical use or development for the therapy of cancer: human or humanized mAbs targeting the immunosuppressive receptor PD-L1, such as Atezolizumab, Durvalumab and Avelumab, have been approved for the treatment of several tumors, including melanoma, non-small cell lung cancer, renal cell carcinoma, urothelial carcinoma, liver carcinoma, microsatellite instable (MI) colorectal cancer and Merkel-cell carcinoma5–7.