TGFB1 and neoplasm: Additionally, CSCs produce immunosuppressive cytokines (like IL-4, IL-10, TGF-β, etc.), and co-inhibitory molecules (like IDO1, PD-L1, and B7-H3) that attract immunosuppressive DCs to suppress the anti-tumor immune system and activate/recruit immune suppressing Tregs [159, 166].