 Mesenchymal stem cells, MSCs, are multipotent stem cells found in nearly all tissues and organs. They can differentiate into multiple lineages, including bone, cartilage, fat, muscle, and nerve cells. MSCs also possess immunoregulatory properties, which allow them to interact with immune cells in both the innate and adaptive immune systems. This interaction leads to immunosuppression of various effector functions, providing a basis for their use in treating immune related diseases. Clinical trials have been conducted using MSCs as a treatment for immune related diseases, such as graft versus host disease, autoimmunity, and chronic inflammatory conditions. The results of these trials have shown that MSCs are safe and effective in treating these diseases. This article was offered by Meng Yuan Wang, Guan Yuan, and Liang Xie.