ERBB2 exon 20 insertions were reported as analogous to EGFR exon 20 insertions and associated with primary resistance to currently approved tyrosine kinase inhibitors because of steric hindrance in the drug-binding pocket and a poor response to immunotherapies in lung adenocarcinoma (27, 28) _ENREF_24. This evidence concerns the gene ERBB2 and lung adenocarcinoma.