In the last 2 years, T-DXd was approved to treat non–small cell lung cancer (NSCLC) with select ERBB2 mutations (4), and tucatinib plus trastuzumab was approved to treat HER2 amplification and/or overexpression in colorectal cancer (CRC) (5). The gene discussed is ERBB2; the disease is non-small cell lung carcinoma.