**11. Conclusion**

In conclusion, leptin is considered an essential pleiotropic adipokine with various effects on biological systems. However, leptin's structural and functional characteristics and its receptors are characterized by a unique signaling mechanism. Focusing on leptin could be a therapeutic approach to manage autoimmune inflammation associated with obesity, cancer, and metabolic diseases. But further research is needed to understand the relationship between leptin on biological systems, as it has complex signaling mechanisms.
