Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is regarded as a curative therapy for a variety of hematological malignancies and nonmalignant diseases. However, donor limitations have restricted the widespread use of allo-HSCT for a long period. The development and success of haploidentical allografts worldwide makes "everyone has a donor" a reality. In the past two decades, researchers have established several haploidentical HSCT (haplo-HSCT) protocols based on different approaches to induce immune tolerance. The representative approaches for haplo-HSCT without in vitro. T cell depletion include granulocyte colony-stimulating factor (G-CSF) plus Anti-human Thymocyte Immunoglobulin (ATG) based (Beijing Protocol) and post-transplantation cyclophosphamide based (PT-Cy, Baltimore Protocol) protocols. Both of two protocols have common problems that need to be solved, including infection transplantation related mortality and disease relapse. The main aim of this study is to explore whether the combined protocol can improve the efficacy of haploidentical transplantation further.

Inclusion Criteria:

1. Patients with AL - CR and/or myelodysplastic syndromes undergoing allogeneic hematopoietic stem cell transplantation for the first time;
2. No gender limit, aged 12 - 65 years;
3. Planned haploidentical donor transplantation, excluding transplantation from maternal and collateral donors;
4. Eastern Cooperative Oncology Group (ECOG) performance status score≤3 points;
5. Baseline organ function tests meet the following criteria:

(1) Left ventricular ejection fraction (LVEF) > 55%; (2) Serum creatinine ≤ 1.5 × upper limit of normal (ULN).

Exclusion Criteria:

1. Patients with severe dysfunction of brain, heart, kidney or liver;
2. Those in refractory malignant status;
3. Patients with other malignancies requiring treatment;
4. Presence of uncontrolled severe active infection clinically;
5. Expected survival period of less than 3 months;
6. History of severe allergic reactions;
7. Pregnant or breastfeeding women; (8)Presence of any condition deemed by the investigator as unsuitable for study enrollment.