In this study, we also show that upregulating NECTIN4 using rosiglitazone, a PPARγ agonist originally developed for the treatment of diabetes, enhances the efficacy of the NECTIN4-CAR T cell therapy, which is particularly important for tumors with low or moderate NECTIN4 expression, both in the EV-naïve and EV-refractory settings to improve the durability of response. Here, NECTIN4 is linked to diabetes mellitus.