Abstract:Immunotherapy has become an important means for the treatment of non-small cell lung cancer except surgery, radiotherapy, chemotherapy and targeted therapy, and has shown significant and lasting effects. Immune checkpoint inhibitors are an important part of tumor immunotherapy ,which can block inhibitory signaling pathways, promote T cell activation, and thereby enhance the body`s anti-tumor immune response. Cytotoxic T lymphocyte antigen 4 and programmed death 1/programmed death ligand 1 inhibitors in the treatment of lung cancer have made breakthrough progress, but still face many challenges. In this paper, the mechanism of ICPIs, clinical research progress and the current dilemma were reviewed, hoping to provide new ideas and methods for the treatment of subsequent NSCLC.