Through secretion of TGF−β and ARG2, CAFs induce M2 polarization of TAMs and expansion of Tregs, while CXCL12 produced by CAFs engages CXCR4 on T cells, forming a “chemokine barrier” that excludes CD8+ T cells from tumor nests (76, 77). Here, CXCR4 is linked to neoplasm.