GZMB and neoplasm: Consistently, RA and anti‐PD‐1 combination treatment led to a remarkable increase in effector molecules including IFN‐γ and GZMB production by tumor‐infiltrating CD8+ T cells compared to that in each treatment alone (Figure S8E,F, Supporting Information), reinforcing that the cytotoxic CD8+ T cell activity was increased after RA and anti‐PD‐1combination treatment.