CHZ868-mediated JAK2 inhibition did not induce the exhaustion of CAR-T cells, maintaining efficacy over repeated tumor challenges and significantly extending survival in mouse models engrafted with JAK2 inhibitor-resistant leukemia cells (median survival, CD19 CAR-T + CHZ868 vs. CD19 CAR-T + DMSO: 32 days vs. 26 days, p = 0.0303). Here, JAK2 is linked to neoplasm.