To improve the effectiveness of our previous A20 CAR4 T cell therapy, which targeted integrin αvβ6 to eliminate CCA cells [17], we engineered A20 CAR5 T cells to co-express A20 CAR4 and secrete anti-PD-L1 scFv, addressing the PD-1/PD-L1 checkpoint pathway (Fig. 2A). Here, CD274 is linked to cholangiocarcinoma.