CD19 and neoplasm: For example, CD19 CAR-T cells with PD-1 integration showed a greater ability to eradicate tumor cells in xenograft models and clinical trials.11,13 Knockout of the receptor of adenosine, a key immunosuppressive metabolite in TME, increased the capacity to inhibit solid tumor growth and development.45,46 On the other hand, several traditional drugs have, surprisingly, been found to regulate CAR-T cell differentiation, which were potential synergists for ACT products.