CCL2, also known as monocyte chemoattractant protein-1 （MCP-1）, is a small cytokine belonging to the CC chemokine family. It is primarily secreted by monocytes, macrophages, and dendritic cells, and plays a crucial role in recruiting monocytes, memory T cells, and dendritic cells to sites of inflammation or tissue injury. CCL2 exerts its effects by binding to its receptor, CCR2, and is involved in various biological processes, including leukocyte chemotaxis, regulation of apoptosis, and modulation of immune responses. This chemokine is also implicated in several diseases, such as atherosclerosis, rheumatoid arthritis, cancers and neurodegenerative disorders, due to its role in promoting inflammation and immune cell infiltration. In conclusion, CCL2 is a multifunctional chemokine with significant roles in inflammation, fibrosis, and cancer. Its expression is tightly regulated and serves as a critical mediator of immune cell recruitment and activation. The diagnostic and therapeutic potential of CCL2 makes it a promising target for addressing a wide range of diseases. Further research into the mechanisms of CCL2 regulation and its interactions with the tumor microenvironment will likely yield new insights and therapeutic strategies.