IL15 and leukemia: For example, the transduction of cord blood (CB)-derived NK cells with a retroviral vector of CAR-CD19 containing IL-15 and suicide caspase-9-based suicide (iC9/CAR.19/IL-15 CB-NK cells) have demonstrated to be efficient in killing CD19-expressing cell lines and primary leukemia cells in vitro, xenograft model, and in the clinical trial (NCT03056339) [9,124].