PDCD1 and clear cell renal carcinoma: The finding of a high median TIS score in renal clear cell carcinomas and the efficacy of PD-1 blockade in this tumor type are consistent with other findings that the immunogenicity of renal clear cell carcinoma tumors cannot be explained solely by mutation or neoantigen load, but is highly correlated with MHC class I antigen presenting machinery expression [30].