PDCD1 and renal cell carcinoma: Since then, inhibitors targeting programmed cell death protein 1 (PD-1 or CD279) and its ligand (PD-L1 or CD274) have gained approval for a broadening array of solid tumors, including melanoma, renal cell carcinoma (RCC), non-small cell lung carcinoma (NSCLC), and urothelial carcinoma, among others (5–8).