In this regard, blockade of the programmed cell death-1 (PD-1)/programmed death ligand-1 (PD-L1) axis in particular has opened up a new horizon in the lung cancer therapeutic landscape, increasing overall survival (OS) not only in patients with advanced NSCLC but also in patients with stage III NSCLC and extensive-stage small-cell lung cancer [4,5,6]. Here, PDCD1 is linked to small cell lung carcinoma.