PDCD1 and clear cell renal carcinoma: We hypothesized that single nucleotide polymorphisms (SNPs) in the <i>PDCD1</i> and <i>CD274</i> genes, encoding PD-1 and PD-L1, are associated with clinicopathological features, PD-L1 immunohistochemical expression, and clinical outcomes in clear cell renal cell carcinoma (ccRCC).