In our study, we found that 9.5% (4/42) of VAFIDH was higher than the maximum VAF of coalteration trunk driver genes (VAFIDH–VAFmax [EGFR/ALK/KRAS/BRAF] > 0.01), which was lower than the expected VAF for IDH active‐site mutations, indicating that they were likely subclonal evolution of branching drivers of lung adenocarcinoma. The gene discussed is IDH2; the disease is lung adenocarcinoma.