This study is open to adults between 18 and 55 years of age who are living with overweight or obesity. People with a body mass index (BMI) from 27 to 40 kg/m2 can join the study. The main purpose of this study is to find out how a medicine called BI 1820237 is tolerated by people with overweight or obesity when taken alone or in combination with a medicine called semaglutide or with a medicine called BI 456906. Participants are divided into different groups. All participants in the study either take different doses of BI 1820237 or placebo. Some of the groups take either semaglutide or BI 456906 in addition. Each participant has an equal chance of being in each group. All participants receive the study medicines as injections under the skin once a week for almost 5 months. Placebo injections look like BI 1820237 injections, but do not contain any medicine. Semaglutide is medicine that is already used for overweight or obesity. BI 456906 is another medicine that is being developed for the treatment of overweight and obesity. Participants are in the study for about 7 months. During this time, they visit the study site regularly. For some of the visits, the participants remain at the study site for 1 or 2 nights. At the study visits, the doctors check the health of the participants and note any health problems that could have been caused by BI 1820237, semaglutide, or BI 456906.