Abstract:Malignant tumors are diseases that seriously threaten human health and social development. Traditional tumor therapies such as surgery, radiotherapy, chemotherapy and targeted therapy cannot fully meet the needs of clinical treatment, and emerging immunotherapy has become a research hotspot in the field of tumor treatment. Immune checkpoint inhibitors (ICIs) have been approved as a tumor immunotherapy method for the treatment of various tumors, such as lung cancer, liver cancer, stomach cancer and colorectal cancer, etc. However, during the clinical use of ICIs, only a small number of patients experienced durable responses, which also led to drug resistance and adverse reactions. Therefore, the identification and development of predictive biomarkers is crucial to improve the therapeutic efficacy of ICIs. The predictive biomarkers of tumor ICIs mainly include tumor biomarkers, tumor microenvironment biomarkers, circulation-related biomarkers, host environmental biomarkers and combinatorial biomarkers. They are of great significance for screening, individualized treatment and prognosis evaluation of tumor patients. This article reviews the advances of predictive markers for tumor ICIs therapy.