CXCR4 and neoplasm: Notably, chemokine receptors, including C-C chemokine receptor type 2, 4, 5, 6, 8, 10 (CCR2, CCR4, CCR5, CCR6, CCR8, CCR10), and C-X-C chemokine receptor type 3, 4 (CXCR3, CXCR4) have been identified as significant factors in the recruitment of Treg cells to the tumor site [57,58,59].