This chapter explores the evolution of cell therapy, from early discoveries to its present role in regenerative medicineRegenerative medicine. The chapter begins by introducing the concept of cell therapy, which harnesses stem cellsStem cells and immune cellsImmune cells to repair and regenerate damaged tissues. It highlights the critical roles of stem cells, with their abilities to self-renew and differentiate, and immune cells, as the body’s defense force, in both natural healing and therapeutic applicationsApplications. The chapter outlines major milestones, such as bone marrow transplants, the discovery of stem cells, and the development of CAR T-cell therapies, which have revolutionized cancer treatment. It addresses current trends like personalized medicine and off-the-shelf therapies, alongside the challenges of patient response variability, side effects, and production costs. EthicalEthics considerations, regulatory frameworks, and the impact of international collaboration are also discussed. Looking ahead, the chapter emphasizes the future potential of cell therapy in treating neurodegenerative diseases, heart conditions, and more, as well as the role of emerging technologies like CRISPR and AI. The narrative concludes by reflecting on the historical journey and the promising future of cell therapy.