TGFB1 and glioblastoma: In parallel, GBM-derived immunosuppressive cytokines such as IL-10, macrophage-inhibitory cytokine 1 (MIC-1), and TGF-β inhibit macrophage phagocytosis and stimulate TAMs to secrete additional IL-10 and TGF-β, further suppressing T-cell activation and proliferation [42, 57].