The development of acquired resistance to osimertinib (Osim) (AZD9291 or TAGRISSOTM), an FDA‐approved third‐generation epidermal growth factor receptor (EGFR) inhibitor for the treatment of EGFR‐mutant nonsmall cell lung cancer (NSCLC), limits the long‐term benefits for patients. The gene discussed is EGFR; the disease is lung cancer.