CD22 and acute lymphoblastic leukemia: Since 2000, five ADCs have received FDA approval for hematologic tumors: gemtuzumab ozogamicin (GO, CD33‐targeting) for acute myeloid leukemia (AML) patients,40, 41 brentuximab vedotin (BV, CD30‐targeting) for Hodgkin's lymphoma (HL) and non‐Hodgkin's lymphoma (NHL) patients,42, 43 inotuzumab ozogamicin (INO, CD22‐targeting) for acute lymphoblastic leukemia (ALL) patients,44 polatuzumab vedotin‐piiq (PV, CD79b‐targeting) for diffuse large B‐cell lymphoma (DLBCL) patients,45 and belantamab mafodotin (BM, B‐cell maturation antigen [BCMA]‐targeting) for multiple myeloma (MM) patients.46