Abstract: Sepsis is a host inflammatory response to a life-threatening infection with severe organ failure and dysfunction. In recent years, despite the tremendous progress in medicine and medical technology, the mortality rate of sepsis is still high (30%-70%). Sepsis is essentially the body's response to infectious factors, and the initial immune response is a state of excessive inflammation that rapidly progresses to an immunosuppressive state. It is important to understand the host cell-mediated immune response involved in the development of organ damage during sepsis. This article reviews the role and mechanisms of immune cells during sepsis in humans and mice.