IL15 and neoplasm: Although a single infusion of 1 × 107 CAR.19+ (without IL15) or CAR.19/IL15+ CB-NK cells both improved tumor control and prolonged survival compared to non-transduced CB-NK, CAR.19/IL15+ CB-NK cells controlled tumor expansion and prolonged survival significantly better than the CAR.CD19 construct lacking the IL-15 gene, which underscores the critical influence of IL-15 in enhancing antitumor activity in vivo (80).