In the context of relapsed or refractory B-ALL, the lymphodepletion strategy entailing the concomitant use of cyclophosphamide and fludarabine has manifested a staggering 94% complete remission rate prior to CD19 CAR-T cell therapy, accompanied by a restructured Disease-free survival (DFS) that surpassed that of the fludarabine-excluded group [15]. This evidence concerns the gene CD19 and precursor B-cell acute lymphoblastic leukemia.