To apply Ivarmacitinib for the prevention of acute graft-versus-host disease (aGVHD) in HLA haploidentical transplantation, the incidence of grade II-IV aGVHD after prevention, the incidence of primary graft failure, the rate of GVHD-free relapse-free survival (GRFS) (12 months), the incidence of infection, the incidence of chronic graft-versus-host disease (cGvHD) (100 days - 1 year), treatment-related mortality, the incidence and severity of cytokine release syndrome (CRS), and the safety of the prevention regimen will be evaluated.