IL15 and neoplasm: As shown in Figures S4A–D, no significant body weight loss was observed in mice treated with H9 CAR-IL15 T cells compared with other groups in all but the B16F10-claudin 18.2 melanoma experiment where the decreased weight increment may be related with reduced tumor growth, which is further supported by the fact that no obvious pathologic damage could be detected in the vital organs from the mice receiving H9 CAR-IL15 T cells (Figure S4E).