A separate taxonomic TCGA analysis that stratified RCC into nine distinct subtypes similarly found the ccRCC clusters to contain the greatest levels of total immune and T cell infiltration, as well as increased expression of the genes for CD3, PD-1, PD-L2, CTLA-4, CD134, and CD137 [5]. Here, CTLA4 is linked to nonpapillary renal cell carcinoma.