CD4 and neoplasm: The percentage of CD4+ TCR-T subsets in mice peripheral blood was higher in IL-21R-TCR-T 7 and 14 days after transfer (Supplementary Fig. 9e), indicating that the IL-21R promoted the persistence of CD4+ TCR-T, which led to the increased amounts of tumor-infiltrating CD4+ TCR-T cells (Supplementary Fig. 9a).