• ≥ 55 years old;

• High risk myeloid malignancies： 1）No hematological remission(NR) after induction/re-induction treatment for AML; 2）Morphological remission but with persistent positive minimal resident disease(MRD) (Flow cytometry\>0.01% and/or fusion gene positive and/or digital polymerase chain reaction(PCR) positive）; 3）High risk acute myeloid leukemia(AML) according to 2022 European Leukemia Net(ELN) risk stratification； 4）High risk myelodysplastic syndrome(MDS): IPSS-R score ≥ middle risk-2; therapy-related MDS; MDS with mutation of ASXL1, EZH2, RUNX1, SRSF2, U2AF1, STAG2, NRAS, ZRSR2, or TP53； 5）High risk chronic myelomonocytic leukemia(CMML), MDS/MPN.

• Patients must have appropriate donor:

⁃ 1）Related donor must be HLA-A, - B, - C, - DQB1 and - DRB1 matched at least 5/10; 2）Unrelated donor must be HLA-A, - B, - C, - DQB1 and - DRB1 matched at least 8/10; 4. Hematopoietic cell transplantation-comorbidity Index(HCT-CI) score ≤ 4。 5. Eastern Cooperative Oncology Group(ECOG) score 0-2。 6. Liver, kidney and cardiopulmonary functions meet the following requirements:

• Creatinine≤1.5×ULN;

• Left ventricular ejection fraction \>50%;

• Baseline oxygen saturation\>92%;

• Total bilirubin≤1.5×ULN；ALT and AST≤2.0×ULN；

• DLCO≥ 40% and FEV1 ≥ 50%。 7. Able to understand and sign the Informed Consent Document.