In current clinical practice, most NSCLC patients with common EGFR mutations receive osimertinib as first-line therapy; however, some EGFR-mutated NSCLC patients are treated with first- or second-generation EGFR-TKIs with/without anti-vascular endothelial growth factor therapy, and these patients still need to receive T790M testing after a failure of first- or second-generation EGFR-TKIs. This evidence concerns the gene EGFR and non-small cell lung carcinoma.