CRLF2 and leukemia: In summary, we demonstrate robust curative potential of TSLPRCART immunotherapy in preclinical models of human CRLF2-rearranged Ph-like ALL and DS-ALL and an optimized time-sequenced JAK inhibitor co-therapy strategy that both mitigates acute CRS-like toxicity and potential CAR T cell exhaustion and maximizes long-term leukemia remission durability.