Interstitial lung disease (ILD)/pneumonitis is one of the prevalent life-threatening adverse events associated with anti-HER2 ADC therapies including trastuzumab emtansine, trastuzumab deruxtecan, and trastuzumab doucamazine [51]; however, the underlying cause of ADC-induced ILD is still poorly understood. Here, ERBB2 is linked to pneumonitis.