Through the secretion of soluble factors, including immunosuppressive cytokines (such as TGF-β, IL-10) (11, 12), chemokines (such as CCL2, CCL5) (13, 14), and exosomes carrying bioactive molecules (15), CSCs actively recruit and reprogram tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), and regulatory T cells (Tregs) toward immunosuppressive phenotypes (16). The gene discussed is CCL2; the disease is neoplasm.