Cellular immunotherapy, particularly with chimeric antigen receptor (CAR)-T cells, has revolutionized cancer treatment approaches. However, the use of patient-derived (autologous) immune cells for therapy presents significant challenges, including limited availability, high costs, and delayed treatment times. To address these limitations, therapies involving allogeneic sources of immune cells are emerging as a promising alternative, offering an off-the-shelf solution for scalable and efficient cancer immunotherapy. Stem cells, particularly hematopoietic stem cells (HSCs) and pluripotent stem cells (PSCs), provide an expandable and renewable source for generating therapeutic immune cells. These cells can be genetically engineered to enhance their tumor-targeting abilities and reduce the risk of immune rejection. Despite their potential, challenges such as graft-versus-host disease (GVHD), immune clearance, and manufacturing complexities remain key hurdles to widespread clinical application. This chapter explores the current landscape of allogeneic stem cells in immunotherapy, focusing on their advantages over autologous sources, current gene-editing strategies, and recent technological advancements that may overcome existing limitations. Through a comprehensive examination of both the opportunities and challenges in this field, we provide insights into the future direction of stem cell-based immunotherapies and their potential impact on cancer treatment paradigms.