Allogeneic hematopoietic stem cell transplantation is the most widely used form of immunotherapy. The allogeneic immune effectors infused with the graft can recognize and eradicate the patients' tumoral cells. The curative potential of allogeneic hematopoietic stem cell transplantation is classically based on two mechanisms: the conditioning myelo-ablative or immunosuppressive inducing either the cytoreduction of tumoral cells or tolerance and the immune control mediated by allogeneic immune effectors (graft-versus-leukemia or tumor effect, GVL or GVT). Allogeneic hematopoietic stem cell transplantation is currently under important mutations because of better understanding of the GVT mechanisms and the development of new treatment techniques with: (a) allo-hematopoietic stem cell transplantation of peripheral blood stem cells after mobilization with G-CSF and allotransplant of cord blood cells; (b) increase number of allogeneic hematopoietic stem cell transplantation from unrelated and haplo-identical donors; (c) immunomodulation according to the chimerism and residual disease documentation with donor lymphocyte infusion (DLI); (d) development of reduced intensity conditioning regimens aiming to reduce the toxicity while favoring the immune component of the anti-tumoral effect; (e) development of sequential chemotherapy followed by allogeneic hematopoietic stem cell transplantation after reduced intensity conditioning in case of refractory diseases. In addition the present experience shows clearly that the allogeneic hematopoietic stem cell transplantation strategy should be developed and refined because of the potential benefit that can be expected in some patients' sub-groups and then allogeneic hematopoietic stem cell transplantation, real immunotherapy should be included in the global therapeutic strategy in onco-hematology.