Stromal Cell-Derived Factor 1 beta （SDF-1β）, also known as CXCL12, is a chemokine protein that plays a crucial role in immune cell trafficking, hematopoiesis, and tissue repair. SDF-1β is produced by stromal cells, endothelial cells, and fibroblasts, and acts as a chemoattractant for a variety of immune cells, including lymphocytes, monocytes, and hematopoietic stem cells. SDF-1β binds to its receptor, CXCR4, and regulates cell migration, adhesion, and survival. This chemokine is involved in various physiological and pathological processes, such as inflammation, angiogenesis, and cancer metastasis.