IL15 and neoplasm: Treatment with a lower dose (2.5 × 106) of H9 CAR-IL15 T cells still produced significantly better antitumor efficacy (Figure 3K, mean tumor volume on Day 21 post CAR-T injection: 51.3 vs. 221.0 mm3, p < 0.0001; Figure 3L, TGI: 90.5% vs. 55.8%, n = 5 for H9 CAR-IL15 vs. H9 CAR); at the end of the observation period (60 days after treatment), 66.7% (4/6) of the mice in this group remained alive, and the overall survival was significantly better than that of the control group (Figure 3M; p < 0.05).