To verify the function of PD1hi CD200hi CD4+ exhausted T cells in vivo, we subcutaneously implanted MB49 bladder cancer cells into immunocompetent mice and treated mice every 2 days with anti‐PD1 antibody when tumours were 50 mm3 in size (Figure 5A,B). This evidence concerns the gene PDCD1 and urinary bladder cancer.