Compared with other IL-2 delivery patterns, including systemic administration, constitutive IL-2 secretion, TCR/CAR activation-induced IL-2 production and paracrine IL-2 replenishment by gene-modified T cells, the conditionally initiated autocrine IL-2 circuit led to preeminent therapeutic outcomes in immunocompetent tumor models [3]. This evidence concerns the gene IL2 and neoplasm.