IL7 and neoplasm: As CCL19 is a chemoattractant for T cells and DCs, and IL-7 is known to enhance the proliferation and survival of T cells16, CAR-T cells that produce IL-7 and CCL19 can recruit T cells and DCs to tumor tissues and enhance T cell viability in the tumor immune-inhibitory microenvironment (TME),which could improve the therapeutic effects of CAR-T cells against solid tumors17.