EGFR C797, G796, L792, L718/G719 and G724 mutations, EGFR gene amplification, MET and HER2 amplification, BRAF, RAS-MAPK and PI3K pathway activation, oncogenic fusion mutations and phenotypic transformation are the emerging resistance mechanisms to osimertinib in EGFR-mutated NSCLC patients. This evidence concerns the gene EGFR and non-small cell lung carcinoma.