Therefore, only the latent and not the active form of TGF‐β is found at high levels in blood serum.26 We have confirmed that the TGF‐β CAR does not respond to the latent form of TGF‐β (Figure 3), thus reducing the risk of non‐specific, systemic activation of TGF‐β CAR‐T cells in non‐tumor tissue. Here, TGFB1 is linked to neoplasm.