CCR4 and neoplasm: The immune escape factors CCL22/CCL17 and CCL2 are particularly interesting chemokines to recruit activating immune cells by genetic engineering, as the selective pressure posed by CCR4/CCR2B-NK cells on tumor cells can be very advantageous: a reduction of these chemokines in response to this treatment in the TME would compromise the recruitment of immunosuppressive immune cells as well.