This study is testing a medicine called **CagriSema** for people who have obesity. Obesity means weighing more than what's considered healthy for your height. The study aims to help people lose weight and keep it off. It has two parts: the **main study** and the **extension study**. In the main study, participants will either get CagriSema or a placebo, which looks like the real medicine but doesn't have any active ingredients. Participants have a higher chance of receiving CagriSema. If you start with CagriSema, you'll continue with it in the extension study. If you start with a placebo, you'll switch to CagriSema in the extension study. The medicine is given as an injection once a week. The study lasts about 3 years and 3 months.

• The study lasts over 3 years, so it's a long-term commitment.
• Participants will receive weekly injections.
• Eligibility includes adults with a BMI of 30 or more, aiming to lose 25% of body weight.