The flow cytometry results showed an induction in the ratio of M1/M2 macrophages in the tumor tissues in the HER2 CAR-M group compared with that in the control group (Fig. 4G), implying that the overall macrophages in the tumor microenvironment of the HER2 CAR-M treatment group were maintained in a tumor-suppressing M1 state. Here, ERBB2 is linked to neoplasm.