Additionally, after repeated stimulation with irradiated SKOV3PD-L1 cells, HER2.28ζ/PD-L1.BB CAR-T cells continued to efficiently kill tumor cells (Fig. 7h, i), accompanied by significantly enhanced production of IFN-γ, IL-2 and TNF-α (Fig. 7j), as well as a stronger and more persistent proliferation, as compared to HER2.28ζ CAR-T cells (Fig. 7k). Here, IL2 is linked to neoplasm.