CCL2 and neoplasm: Moreover, tumor-derived, immunosuppressive signaling molecules such as IL-10, TGF-β, VEGF, and prostaglandin E2, as well as the expression of checkpoint molecules such as PD-L1 and CTLA-4, pave the way for the recruitment of MDSCs, TAMs, and Treg, orchestrated by tumor cell-derived chemokines such as CCL2, CSF1, CCL5, CCL22, CXCL5, CXCL8, and CXCL12 [15,30,31,32,33,34,35,36,37].