IL10 and neoplasm: In contrast, pro-tumor subsets like Bregs secrete immunosuppressive cytokines (e.g., IL-10, TGF-β) to inhibit effector T/NK cells and promote Treg differentiation, while exhausted or aged B cells impair antigen presentation and express high levels of immune checkpoints (e.g., PD-1, TIM-1) to exhaust T cells (128).