CCR4 and colorectal carcinoma: These include: CC chemokine receptor 4 (CCR4), attracted to inflammatory loci by the ligands CCL22 or CCL17 produced by CRC tumor cells or macrophages (142); CCR5, highly expressed in TI-Treg cells and associated with Treg cell recruitment towards the ligands CCL3, and CCL4 expressed by CRC tumor cells (34, 143); CCR6, involved in migration to the TME in response to CCL20 produced by tumor-associated macrophages (144, 145); CCR8, exclusively expressed by TI-Treg cells (146) and CCL1, expressed by tumor-infiltrating myeloid cells (128).