CCL22 and neoplasm: Specifically, tumor-associated macrophages (TAMs) and cancer-associated fibroblasts (CAFs) induce the upregulation of regulatory T cells (Tregs) through the release of interleukin-10 (IL-10), transforming growth factor-beta (TGF-β), and C-C motif chemokine ligand 22 (CCL22) [16,17].