The goal of this clinical trial is to evaluate the effectiveness and safety of the anti-NKG2A monoclonal antibody (Monalizumab) in patients undergoing haploidentical stem cell transplantation (Haplo-SCT) with post-transplantation cyclophosphamide (PT-Cy). The main questions this trial aims to answer are:
* Does Monalizumab improve graft-versus-host disease-free and progression-free survival (GPFS) in patients after Haplo-SCT?
* What are the safety and side effects of Monalizumab in this patient group?
* How does Monalizumab affect the reconstitution and function of NK cells in patients undergoing Haplo-SCT?
* Researchers will administer Monalizumab to participants on day +30 and +44 after transplantation to see if it enhances immune responses and prevents disease relapse or GVHD.
Participants will:
* Receive Monalizumab intravenously at 1 mg/kg on day +30 and day +44 after Haplo-SCT
* Be monitored for clinical outcomes such as GVHD, survival rates, and immune function for up to one year after the transplant
* Undergo regular checkups and tests to assess the effectiveness and safety of the treatment