Abstract: In recent years, tumor immunotherapy with immune checkpoint as the target has attracted much attention because of its remarkable efficacy. However, with the application of immune-checkpoint inhibitors (ICIs), more and more immune-related adverse events (irAEs) have been reported. IrAEs impose an additional risk of death on tumor patients treated with ICIs, limiting the widespread use of ICIs. To help patients actively prevent irAEs, biomarkers with the predictive value of irAEs are of great significance. This paper reviews the biomarkers with predictive value for irAEs from the aspects of serology, genetics and microbiology.