CD22 and acute lymphoblastic leukemia: Studies treating ALL patients were based on CD22/CD19 dual‐targeting CAR‐T‐cell treatment alone, including one study using bicistronic vector,33 two trials conducting cotransduction of CAR‐T cells, five studies infusing coadministration of CD22 and CD19 CAR‐T cell product36, 38, 39 and eight trials utilizing tandem CAR‐T cells.31, 34, 35