Additional Study Information: The purpose of the study is to see if a medicine called gilteritinib/ASP2215 given in combination with atezolizumab is both effective and safe as a treatment for AML patients with mutations in the FLT3 gene. Some AML patients have a mutation in the gene called FLT3. When patients have a FLT3 mutation, more of the FLT3 protein is on the leukemic cells, or the protein is more active. This may make the leukemic cells grow faster or live longer. Gilteritinib/ASP2215 is an experimental drug that is being studied to treat AML. It is being tested in clinical trials and has not been approved by U.S. Food and Drug Administration (FDA) and/or any other regulatory authorities for any indication.