This study will consist of two parts. Part 1 will assess the safety, tolerability, and efficacy of gocatamig and I-DXd at doses determined in study MK-6070-001 (NCT: NCT04471727). Part 2 will assess the safety and tolerability of gocatamig in participants in Japan and China. Part 3 will assess the safety, tolerability, and efficacy of gocatamig with durvalumab.