The mechanism and research progress of PD-1/PD-L1 on immune escape of lung cancer.

According to the latest Global Cancer Observatory (GLOBOCAN) 2022 estimates, lung cancer remains the second most commonly diagnosed cancer worldwide, with approximately 2.48 million new cases (11.4% of all cancer diagnoses) and over 1.86 million deaths (18.2% of all cancer-related deaths), making it the leading cause of cancer mortality globally. It has been reported that programmed death ligand 1 (PD-L1) is confirmed to interact with the tumor microenvironment (TME) to mediate the immune escape of lung cancer. PD-L1, which is highly expressed in lung cancer cells, activates the programmed death receptor 1 (PD-1)/PD-L1 signaling pathway by binding to PD-1, thereby inhibiting the function of lymphocytes and the release of cytokines, inducing activated lymphocyte apoptosis, resisting the killing effect of lymphocytes, ultimately leading to immune escape in lung cancer. PD-L1 inhibitors, a hot spot in tumor immunotherapy, can restore the activity of T cells, thereby enhancing the body's immune response, and ultimately enabling the immune system to effectively recognize and kill lung cancer cells, thereby enabling lung cancer patients to achieve long-term tumor remission. At present, a variety of PD-L1 inhibitors have been approved for application and have achieved good clinical efficacy in the treatment of lung cancer. This article reviews the research progress of the interaction between PD-L1 and the TME to mediate immune escape from lung cancer and the role of PD-L1 inhibitors in the treatment of lung cancer.