Secondly, CAFs indirectly support tumour progression by remodelling the immune microenvironment: on the one hand, it suppresses both CD8+ T cell infiltration and function by recruiting MDSCs and Tregs; on the other hand, TGF-β released by CAFs induces the polarisation of M2-type macrophages and promotes the depletion of T cells by delivering molecules such as miR-1228-3p via exosomes to form a multi-layered immune escape barrier [30–32]. This evidence concerns the gene TGFB1 and neoplasm.