PDCD1 and non-small cell lung carcinoma: Numerous studies in human NSCLC patients or a mouse model of EGFR-driven adenocarcinomas have implicated hyperactivation of the PD-1-PD-L1 axis in tumor immune escape and malignant progression (45–47), and manipulation of Treg generation driven by this axis constitutes one of the most predominant mechanisms of NSCLC occurrence (Figure 1B).