In 2010, the first phase I clinical trial of an anti-PD-1 antibody, nivolumab, was conducted in 39 patients with treatment-refractory solid tumors such as advanced melanoma, non-small cell lung cancer (NSCLC), renal cell carcinoma (RCC), prostate cancer, and colorectal cancer (CRC). Here, PDCD1 is linked to renal cell carcinoma.