PDCD1 and lung cancer: Non-Small Cell Lung Cancer (NSCLC) accounts for about 85% of all types of lung cancer (2) In recent years, immune checkpoint inhibitors (ICI), especially programmed death receptor 1 (PD-1) and its ligand 1 (PD-L1), have been widely used.PD-1/PD-L1 inhibitors have significantly improved the treatment of patients with advanced NSCLC (3).