A Study to Learn About the Tests Looking for a Gene Mutation in Adults With Lung Cancer in China (ELEGANT)

This is a non-interventional, retrospective, observational study of the Chinese participants with locally advanced or metastatic NSCLC with EGFR ex20ins mutation. The primary objective of this study is to explore the prevalence of EGFR ex20ins, subtypes of EGFR ex20ins and their frequency in Chinese participants with locally advanced or metastatic NSCLC. The study will enroll approximately 10800 patients. Participants will be enrolled in the following two cohorts: * Cohort 1: Participants With Positive EGFR ex20ins Detection * Cohort 2: Participants With Positive and Negative EGFR ex20ins Detection The data will be collected retrospectively using the participant electronic medical records and next-generation gene sequencing (NGS)/polymerase chain reaction (PCR) kit instructions. This multi-center trial will be conducted at 15 sites across China. The overall time to participate and data collection will be approximately 12 months.