An attractive alternative is allogeneic cell replacement therapy, which involves transplanting iPSC-derived cells generated from one patient into a different patient's body. Although this strategy is less costly and more widely applicable, it raises concerns about the potential for immune rejection of grafts and the need for immunosuppressants, which can increase the risk of cancer and serious infections. There has been an ongoing controversy as to whether the safety and effectiveness of allogeneic cell replacement therapy could be improved through the use of iPSC-derived cells generated from immunologically matched donors.