CD33 and acute myeloid leukemia: Stimulated by both the success of GO as well as its limitations, CD33 has remained of great interest for drug development in AML and a widening range of other malignant and non-malignant diseases, with ongoing efforts with several classes of therapeutics, including newer-generation antibody–drug conjugates, radiolabeled antibodies, bi- and tri-specific antibodies, as well as CAR-modified IECs [72,75].