PDCD1 and hereditary clear cell renal cell carcinoma: Targeting immune checkpoints by blocking monoclonal antibodies, including anti-programmed cell death protein 1 (PD-1) or anti-PD-L1 antibody, have provided clinical benefits for patients with advanced metastatic melanoma, non-small cell lung cancer (NSCLC), renal cell carcinoma (RCC), and several other cancers2.