Through anti‐PD‐1 therapy and combined injection of a cell vaccine based on the combination of DC cells with C‐C motif chemokine ligand 21 (CCL21) and tumor antigen, it was found that the combined therapy could increase the activity of DCs and tumo C‐C motif chemokine ligand 21r infiltrating T cells in the TME and induced mice to produce immune memory in the tumor mouse model induced by K‐RasG12Dp53null.122. This evidence concerns the gene CCL21 and neoplasm.