The article reviews the role of sphingosine-1-phosphate (S1P) in immune cell trafficking and inflammation. S1P, a lipid signaling molecule, plays a crucial role in both innate and adaptive immune responses. It is involved in the regulation of immune cell migration, activation, and differentiation, and its levels are tightly controlled by sphingosine kinases (SphKs) and S1P receptors (S1PRs). During inflammation, the S1P gradient is altered, affecting lymphocyte trafficking and immune cell recruitment to the inflammatory site. The review highlights the mechanisms by which S1P signaling is regulated in inflammation and how it shapes immune responses through immune cells. It also discusses the therapeutic potential of S1P receptor modulators in treating inflammatory diseases, including multiple sclerosis, autoimmune diseases, and sepsis. The authors emphasize the importance of understanding the complex metabolism and distribution of S1P in maintaining immune homeostasis and regulating inflammatory responses.The article reviews the role of sphingosine-1-phosphate (S1P) in immune cell trafficking and inflammation. S1P, a lipid signaling molecule, plays a crucial role in both innate and adaptive immune responses. It is involved in the regulation of immune cell migration, activation, and differentiation, and its levels are tightly controlled by sphingosine kinases (SphKs) and S1P receptors (S1PRs). During inflammation, the S1P gradient is altered, affecting lymphocyte trafficking and immune cell recruitment to the inflammatory site. The review highlights the mechanisms by which S1P signaling is regulated in inflammation and how it shapes immune responses through immune cells. It also discusses the therapeutic potential of S1P receptor modulators in treating inflammatory diseases, including multiple sclerosis, autoimmune diseases, and sepsis. The authors emphasize the importance of understanding the complex metabolism and distribution of S1P in maintaining immune homeostasis and regulating inflammatory responses.