EGFR and non-small cell lung carcinoma: In xenograft mice, MET amplification only developed in PD-L1 overexpression, but not in PD-L1 knock-out and parental NCI-H1975 cells, at the time of osimertinib resistance.<h4>Conclusion</h4>In EGFR-mutant NSCLC, PD-L1 regulates c-MET phosphorylation and promotes MET amplification, contributing to osimertinib resistance.