Growth differentiation factor-15 (GDF-15), also known as macrophage inhibitory cytokine-1 (MIC-1), is a member of the transforming growth factor-β (TGF-β) superfamily. It is a stress-responsive cytokine that is produced by various cell types including macrophages, vascular smooth muscle cells, cardiomyocytes, adipocytes, and endothelial cells. GDF-15 is typically expressed at low levels in most tissues but can be significantly induced under conditions of tissue injury, hypoxia, and inflammatory cytokine responses. It plays a role in various biological processes such as organ growth, differentiation, development, and cellular repair. Notably, GDF-15 has been identified as a biomarker for disease prognosis, particularly in cardiovascular diseases, cancer, and metabolic disorders. The cytokine has also been implicated in immune modulation and has been proposed as a potential target for therapeutic intervention in conditions like obesity, diabetes, and cardiovascular diseases. Its role as an immune checkpoint and its potential as a target for cancer immunotherapy are areas of active research.