The purpose of this study is to assess Tacrolimus/Methotrexate/Ruxolitinib versus Post-Transplant Cyclophosphamide/Tacrolimus/Mycophenolate Mofetil in Non-Myeloablative/Reduced Intensity Conditioning Allogeneic Peripheral Blood Stem Cell Transplantation

This study will evaluate the safety, tolerability, and efficacy of Orca-T in participants undergoing reduced intensity or non-myeloablative allogeneic hematopoietic cell transplantation (alloHCT) for hematologic malignancies. Orca-T is an allogeneic stem cell and T-cell immunotherapy biologic manufactured for each patient (transplant recipient) from the mobilized peripheral blood of a specific, unique donor. It is composed of purified hematopoietic stem and progenitor cells (HSPCs), purified regulatory T cells (Tregs), and conventional T cells (Tcons).