TGFB1 and neoplasm: The clinical efficacy of CAR‐T cell therapy for solid tumors is restricted by the immunosuppressive TME, such as hypoxia, immunosuppressive signaling by cellular immune checkpoint receptors, oxidative stress, and tumor‐derived cytokine suppression, etc.97, 98Meanwhile, previous studies have demonstrated that tumor cells can release a variety of immunosuppressive factors, including VEGF, IL‐4, IL‐10, TGF‐β, and prostaglandin E2, leading to the activation of suppressive immune cells such as regulatory T cells, myeloid‐derived suppressor cells, and tumor‐associated macrophages.99