CD274 and renal cell carcinoma: When PD-L1 expression was assessed in various RCC trials including Checkmate 025 (nivolumab), Checkmate 214 (ipilimumab/nivolumab), and KEYNOTE-426 (pembrolizumab plus axitinib), the expression did not completely predict responsiveness to these checkpoint inhibitors and patients’ outcomes were predominately not dependent on PD-L1 expression [89].