CCL3, also known as macrophage inflammatory protein-1 alpha (MIP-1α), belongs to the CC chemokine family and is a small-molecule cytokine secreted by activated immune cells such as T cells and macrophages. Its primary function is to bind to and activate the chemokine receptors CCR1 and CCR5 on cell surfaces, thereby recruiting and activating various immune cells including monocytes, macrophages, T cells, and dendritic cells. This plays a critical role in infection defense, inflammatory responses, and tumor immune surveillance. Research indicates that CCL3 is aberrantly expressed in conditions such as rheumatoid arthritis, HIV infection, and the microenvironment of various tumors, making it an important therapeutic target for inflammatory diseases and tumor immunotherapy. Receptor antagonists targeting its pathway, such as anti-CCR5 drugs, have already been applied in clinical practice.