RecruitingPhase 1Biological interventionA Study of ADCLEC.syn1 in People With Acute Myeloid LeukemiaThe purpose of this study is to test the safety of ADCLEC.syn1 CAR T cells in people with relapsed or refractory AML. The researchers will try to find the highest dose of ADCLEC.syn1 CAR T cells that causes few or mild side effects in participants. Once the researchers find this dose, it will test it in a new group of participants to see if it is effective in treating their relapsed/refractory AML.