TGFB1 and neoplasm: Tumor-derived exosomes carry PD-L1, TGF-β, and immunomodulatory microRNAs that inhibit T cell responses and promote immunosuppressive cell recruitment (Olejarz et al., 2020; Raimondo et al., 2020; Hao et al., 2022; Sheta et al., 2023).