Based on these findings, the same authors undertook a phase 1 and 2 trial to assess the safety and efficacy of escalating doses of HLA-mismatched, CB-derived iC9/CAR.19/IL-15 CAR-NK cells for the treatment of relapsed or refractory CD19-positive B-lymphoid malignancies, including CLL [42]. This evidence concerns the gene IL15 and B-cell chronic lymphocytic leukemia.