ERBB2 and breast cancer: This review covers the basic biology behind the structure and mechanism of action of ADCs, summarizes the advantages ADCs have in overcoming therapeutic resistance, discusses the metabolic profile of ADCs, lists several ADCs currently under development, and includes up-to-date in-depth information on FDA-approved ADCs for the treatment of HER2-positive and, most recently, HER2-low breast cancer along with their toxicity profiles and current ongoing clinical trials.