EGFR tyrosine kinase inhibitors are the standard-of-care treatment for EGFR-mutant non-small cell lung cancer, but tumors frequently develop acquired drug resistance. Targeting the EGFR dimerization partner HER3 has the potential to improve efficacy of EGFR inhibitors. The HER3 antibody–drug conjugate patritumab deruxtecan (red) is shown binding the extracellular domain of HER3 (blue). EGFR (white) inhibition with an EGFR tyrosine kinase inhibitor (depicted as a black intracellular domain) leads to an increase in cell surface HER3. For details, see the article by Haikala and colleagues on page 130.