A Study to Test How Well Different Doses of BI 3822971 Are Tolerated by People With Advanced Cancer (Solid Tumours)

This study is open to adults with advanced or metastatic solid cancer, such as non-small cell lung cancer, head and neck squamous cell carcinoma, triple-negative breast cancer, esophageal squamous cell carcinoma, bladder cancer, vulvar cancer, and cervical cancer. People can join the study if they have no remaining standard treatment options and have a measurable lesion outside the central nervous system. The purpose of this study is to find out how well a medicine called BI 3822971 is tolerated in people with these cancers. Researchers also want to find a dose and dosing schedule of BI 3822971 that is safe and is well tolerated. In this study, BI 3822971 is given to humans for the first time. BI 3822971 is being developed to help the immune system fight cancer. This schedule can change during the course of the trial depending on the data generated. All participants receive the study medicine (there is no randomization and no placebo group). Participants visit the study site and may need to stay overnight for observation, especially on days when the medicine is administered. Participants can stay in the study for up to 3 years as long as they benefit from treatment and can tolerate it. During this time, doctors regularly check the size of the tumour. The doctors also regularly check participants' health and take note of any unwanted effects. They collect information on any health problems of the participants and take blood samples.