PDCD1 and renal cell carcinoma: Immune checkpoint inhibitors have also made significant progress in RCC treatment in recent years, working by blocking immune suppression pathways and enhancing the immune system’s ability to recognize and kill cancer cells, with programmed cell death 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors being the main options [78].