When H9 CAR-IL15 T cells were stimulated by antigen-positive tumor cells, we detected only slight IL-15 production, whereas significant IL-15 was detected after CD3/CD28 bead stimulation, different from previous studies where significant IL-15 was detected by IL-15-expressing mouse or human CAR-T cells after cognate antigen stimulation (19). This evidence concerns the gene CD28 and neoplasm.