Abstract： Objectives To mine the immune-related adverse event(irAE)signals of pembrolizumab,nivolumab,atezolizumab and durvalumab based on the FDA Adverse Event Reporting System(FAERS),so as to provide guidance and reference for reducing clinical risks and post-marketing safety monitoring.Methods Adverse event reports were extracted from the fourth quarter of 2012 to the first quarter of 2022 in FAERS.The reporting odds ratio(ROR),comprehensive stan-dard method(MHRA)and Bayesian confidence propagation neural network(BCPNN)were used to conduct signal detection.Standardized MedDRA Queries(SMQ)was applied to broadly retrieve signals about irAEs in immune-mediated/autoim-mune diseases,which aimed to analyze the common characteristics of irAEs caused by the four PD-1/PD-L1 inhibitors.Results Statistical analysis results revealed that the number of adverse events reported for nivolumab was the highest and increased the most year by year.Male and elderly patients constituted a larger proportion of those experiencing adverse events,and the main clinical outcomes were other serious important medical events,hospitalization and death.Signal detec-tion results identified a total of 23 signals for irAEs across the four PD-1/PD-L1 inhibitors,including encephalitis,myas-thenia gravis,thyroid disorders,pemphigoid,colitis,myositis,hepatitis,and fulminant type 1 diabetes and so on,affecting 11 system organ classes(SOC).Age-specific signals were more prevalent and predominantly manifested as immune throm-bocytopenia in addition to myositis and myocarditis among the elderly population.Conclusion Signals about irAEs induced by PD-1/PD-L1 inhibitors affect a wide range of SOC.Therefore,it is recommended that clinicians obtain a detailed history of the patient's previous illnesses before administering the drug.Special attention should be paid to the risk of drug use in the el-derly population.Early management and prompt assessment of irAEs should be strengthened.Emphasis should be placed on collecting and analyzing immune-related adverse event data in the Chinese drug-using population to identify its adverse reac-tion characteristics and continuously improve the drug's package insert.This approach will promote the safe and rational use of PD-1/PD-L1 inhibitors in clinical practice in China.