Abstract: The theory of tumor immunity has gone through more than a century of exploration and shown remarkable clinical efficacy. Therapy based on targeting immune checkpoints, especially anti-CTLA-4 and anti-PD-1/PD-L1 monoclonal antibody monotherapy, has made significant progress in the treatment of advanced lung cancer. Consequently, the discovery of new immune checkpoints has become an area of interest. Additionally, combined immunotherapy is expected to be the future direction of immunotherapy. However, at this stage, immunotherapy has not yet resulted in widespread benefit. Identifying immune resistance mechanisms will further promote individualized treatment.