IL2 and neoplasm: In addition, the effector cytokines in peritoneal lavage fluids including IFN-γ, IL-2 and TNF-α were significantly increased in HER2.28ζ/PD-L1.BB CAR-T cell-treated mice (Fig. 5m), which has also been reported by others that the cytokine secretion of CAR-T cells was enhanced after PD-1/PD-L1 blockade.34 For long-term in vivo persistence, peritoneal lavage fluid was collected 2 weeks after tumor regression (day 34).