Up to now, three ADCs, i.e. brentuximab vedotin, trastuzumab emtansine, and traztuzumab deruxtecan [25, 26, 27, 28, 29, 30, 31, 32, 33], have been approved by FDA to treat relapsed Hodgkin lymphoma and systemic anaplastic large cell lymphoma [34], relapsed or chemorefractory HER2‐positive BC [35], and previously treated or advanced HER2‐psotive BC [32, 33], respectively. Here, ERBB2 is linked to breast cancer.