The primary purpose of this study is to evaluate the safety, tolerability, and pharmacokinetic (PK) parameters of the combination of APG777 + APG990 in adults with moderate-to-severe atopic dermatitis (AD), in comparison to dupilumab. The duration of the study will be approximately 82 weeks for each participant and will consist of a Screening Period (up to 6 weeks), Treatment Period (Baseline-Week 24), and Follow-up Period (Week 28-Week 76).