A Study in People With Advanced Cancer to Test How Well Different Doses of BI 3819026 Are Tolerated When Taken Alone and Together With Ezabenlimab

This study is open to adults with advanced cancer. The purpose of this study is to find the highest dose of BI 3819026 that people with advanced cancer can tolerate when taken alone and together with ezabenlimab. BI 3819026 and ezabenlimab are study medicines that may fight cancer. Participants first receive one treatment of BI 3819026 alone, followed by treatment with a combination of BI 3819026 and ezabenlimab. Different doses of BI3819026 are given to small groups of participants, starting with the lowest dose. Treatment with the next higher dose of BI 3819026 starts only if the previous dose was tolerated. Each participant remains on the same dose of BI 3819026 throughout the study. Participants are in the study for up to 2 years as long as they can tolerate the treatment and their condition does not get worse. During this time, they visit the study site regularly. The doctors look at the occurrence of certain health problems. They also regularly take blood samples, image participants' tumours, and take note of any unwanted effects.