Immunotherapy has been playing an important role in the treatment strategy of lung cancer, among which PD-1/PD-L1 immune checkpoint inhibitors have become a research hotspot in this field. PD-1/PD-L1 inhibitors can reactivate the host’s antitumor immune response by blocking the PD-1/PD-L1 pathway. Numerous clinical studies have shown that it can significantly improve the clinical endpoint of multiple types of cancers, including lung cancer. Based on the results of various clinical studies, there are four PD-1/PD-L1 inhibitors -- Pembrolizumab, Nivolumab, Atezolizumab and Durvalumab have been approved by the FDA for the first-line, second-line or consolidation treatment of non-small cell lung cancer or small cell lung cancer. This article reviews the progress of PD-1/PD-L1 inhibitors in clinical trials of lung cancer, including the efficacy, safety and predictive biomarkers of single or combined drugs, in order to provide evidence for the clinical application of lung cancer immunotherapy.