Taken together, these results indicate that even if the starting population for therapeutic T‐cell manufacturing contains Treg cells, transduction with TGF‐β CAR would not lead to the preferential expansion of Treg cells, and the presence of any TGF‐β CAR‐Treg cells is unlikely to induce suppressive effects on the activity of tumor‐targeting Teff cells. The gene discussed is TGFB1; the disease is neoplasm.