EGFR exon 20 insertions (EGFR e20ins) account for up to 10% of EGFR mutations in lung cancer; however, tumors with EGFR e20ins had poor response rates to EGFR tyrosine kinase inhibitors (TKIs) including gefitinib, erlotinib, afatinib, and osimertinib, and the heterogeneity of EGFR e20ins further complicates the clinical studies. This evidence concerns the gene EGFR and lung cancer.