Given the importance of CD8+ T cells in colitis-related changes during anti-PD-1 immunotherapy, we evaluated the quantity of CD8+ T cells by immunofluorescence staining, the results showed that CD8+ T cells increased significantly after anti-PD-1 treatment, on the contrary, we found that CD8+ T cells decreased in sirolimus treatment alone and when combined with anti-PD-1 (Figures 5A, B). This evidence concerns the gene PDCD1 and colitis.