Of note, regardless enforced exofucosylation of CAR T cells, IL‐2‐expanded CD19‐CAR T cells showed a better control of the disease coupled to a higher T‐cell persistence than IL7‐/IL‐15‐expanded CD19‐CAR T cells in all the in‐vivo leukemia models employed in the present study (NALM6, SEM, and PDXs), suggesting that adequate T‐cell expansion protocols may benefit the manufacturing and clinical outcome of CAR T cells. This evidence concerns the gene CD19 and leukemia.