The main purpose of this study is to demonstrate that when participants with moderate to severe plaque psoriasis and obesity or overweight in the presence of at least 1 weight-related comorbid condition receive ixekizumab and tirzepatide concomitantly administered, participants see improvement in their psoriasis and achieve weight reduction compared to when receiving ixekizumab. Participation in this study includes up to 12 visits and could last up to 61 weeks including screening, open label treatment period, and post-treatment follow-up period.