FOXP3 and neoplasm: Based on flow cytometry, we found that FAP-CAR T cells followed by subsequent Meso-CAR T cells treatment increased the infiltration of endogenous CD8+ T cells in the tumor sites and a concomitant decrease in CD4+FoxP3+ Treg cells (Fig. 8b and Supplementary Fig. 12b, c) and increase in IFN-γ expression in endogenous CD8+ T cells after restimulation compared to other combinations (Fig. 8c).