This article systematically reviews the immune imbalance state and related mechanisms of patients with sepsis, and summarizes new immunotherapy strategies such as immune stimulatory factors (GM-CSF, IL-7, IL-15), immune checkpoint inhibitors (anti-PD-1/PD-L1, anti-CTLA-4, anti-TIM-3), and emerging therapies (mesenchymal stem cells, calprotectin inhibitors, TREM-1 inhibitors). The gene discussed is PDCD1; the disease is Sepsis.