After RBCK1 expression of ccRCC was confirmed, we found a significantly decreased number of infiltrated CD4+ T cells, CD4+FOXP3+ Treg cells, CD68+CD163− M1 macrophages, and CD56bight/dim NK cells in the immune-cold RBCK1high group using opal multi-marker immunohistochemistry staining (Figures 9E, F). Here, CD4 is linked to nonpapillary renal cell carcinoma.