CD33 and acute myeloid leukemia: While CD19 is rarely expressed in AML cells, CAR T cells targeting CD33; CD38; and CD123 have demonstrated efficacy for the treatment of post-allo-HCT AML relapse (108, 109), while CAR T cells targeting CLL1; CD13; and TIM3 among others are in development for the treatment of relapsed/refractory AML (110, 111).