Inclusion Criteria:

          -  Age ≥18 to ≤70 years

          -  Meets one of the following disease and risk categories:

               -  High-Risk Acute Myeloid Leukemia (AML) with predicted risk of relapse higher than
                  30%, which includes, but not limited to the following:

                    -  Patients in morphological remission (CR1 or beyond) with minimal residual
                       disease as quantified either by flow cytometry, or by cytogenetics or
                       molecular markers.

                    -  Patients with the following karyotypes in morphological CR or CRi:
                       ELN-Intermediate I, Adverse, ELN-Intermediate-II. (18) (Examples include
                       monosomal karyotype, complex karyotype, mutant p53, mutant RUNX1, mutant
                       ASXL1, mutant FLT3-ITD, mutant DNMT3A, Inversion 3, T(6:9), KIT mutated core
                       binding factor AML)

               -  Treatment-Related AML and Secondary AML in morphological remission (CR1 or
                  beyond) with minimal residual disease as quantified either by flow cytometry, or
                  by cytogenetics or molecular markers

               -  Myelodysplastic Syndrome (MDS) with < 5% blasts by morphology and meets at least
                  one of the following:

                    -  Received intensive induction chemotherapy (i.e. 7+3 or MEC) OR

                    -  Progression after 4 cycles of hypomethylating agents

               -  The donor and recipient must be HLA identical for at least one haplotype (using
                  high resolution DNA based typing) at the following genetic loci: HLA-A, HLA-B,
                  HLA-C, and HLA-DRB1

          -  Karnofsky performance status ≥ 60% (appendix IV)

          -  Adequate organ function within 14 days of study registration (30 days for pulmonary
             and cardiac) defined as:

               -  Hepatic: AST and ALT < 3 x upper limit of institutional normal

               -  Renal: estimated glomerular filtration rate (GFR) ≥ 40 mL/min/1.73m2

               -  Pulmonary: oxygen saturation ≥ 90% on room air with no symptomatic pulmonary
                  disease. If symptomatic or prior known impairment DLCOcor ≥ 40%.

               -  Cardiac: LVEF ≥ 40% by echocardiography, MUGA, or cardiac MRI, no uncontrolled
                  angina, severe uncontrolled ventricular arrhythmias, or electrocardiographic
                  evidence of acute ischemia or active conduction system abnormalities

          -  Able to be off prednisone or other immunosuppressive medications for at least 3 days
             prior to transplant (excluding preparative regimen pre-medications)

          -  Sexually active females of child bearing potential and males with partners of child
             bearing potential must agree to use effective contraception during therapy and for 4
             months after completion of therapy

          -  Voluntary written consent prior to the performance of any research related procedures

        Exclusion Criteria:

          -  Acute leukemias of ambiguous lineage

          -  Allogeneic transplant for AML within the previous 6 months (no time limit for
             autologous transplant)

          -  Active CNS disease - if a history of AML related CNS involvement, screening CSF
             analysis must be negative

          -  Pregnant or breastfeeding - The agents used in this study include those that fall
             under Pregnancy Category D - have known teratogenic potential. Women of child bearing
             potential must have a negative pregnancy test at screening

          -  Active autoimmune disease requiring systemic immunosuppressive therapy

          -  History of severe asthma and currently on systemic chronic medications (mild asthma
             requiring inhaled steroids only is eligible)

          -  New or progressive pulmonary infiltrates on screening chest x-ray or chest CT scan
             unless cleared for study by Pulmonary. Infiltrates attributed to infection must be
             stable/improving (with associated clinical improvement) after 1 week of appropriate
             therapy (4 weeks for presumed or documented fungal infections).

          -  Uncontrolled bacterial, fungal or viral infections including HIV-1/2 or active
             hepatitis C/B - chronic asymptomatic viral hepatitis is allowed

          -  Active concomitant second malignancy (i.e. has required treatment in the previous 6
             months)

          -  Known hypersensitivity to any of the study agents

          -  Received any investigational drugs within the 14 days before 1st dose of fludarabine