A Study to Test How Well Different Doses of BI 1831169 in Combination With an Anti-PD1 Antibody Are Tolerated in Japanese People With Different Advanced Cancers

This study is open to Japanese adults with different types of advanced cancer (solid tumors). People can join the study if their cancer has spread, and previous treatments were not successful or no treatments exist. The purpose of this study is to find the highest dose of a medicine called BI 1831169 that people can tolerate when taken together with an anti-PD1 antibody. The anti-PD1 antibody is already used to treat different cancers. Participants receive BI 1831169 together with an anti-PD1 antibody, which is given as an infusion into a vein for up to 1 year. Participants visit the study site regularly. The number of site visits vary based on the study part and treatment response. Some visits include an overnight stay. The doctors regularly check the participants' health and monitor the tumors. The doctors also take note of any health problems that could have been caused by the study treatment.

Inclusion criteria * Histologically or cytologically confirmed diagnosis of advanced/metastatic solid tumours * Has at least 1 accessible lesion with a minimum lesion diameter (≥1 cm) for injection of BI 1831169. Lesions must either be easily accessible, or, if not easily accessible, patients must be willing to undergo repeat procedures for injections of BI 1831169. * Has failed conventional treatment or for whom no therapy of proven efficacy exists or who is not eligible for established treatment options. Patients must have exhausted available treatment options known to prolong survival for their disease. * Medically fit and willing to undergo all mandatory trial procedures * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, and life expectancy of at least ≥3 months after the start of the treatment, according to the investigator's judgement * Adequate organ function or bone marrow reserve as demonstrated at screening by the following laboratory values: * Absolute neutrophil count ≥1.5x10\^9/L (≥1.5x10\^3/μL, ≥1500/mm\^3) without white blood cell growth factor support within 4 weeks of start of trial treatment; platelet count ≥100·10\^9/L (≥100·10\^3/μL, ≥100·10\^3/mm\^3), without platelet transfusion within 2 weeks of start of trial treatment * Haemoglobin ≥90 g/L (≥9.0 g/dL, ≥5.6 mmol/L) * Creatinine ≤1.5x upper limit of normal (ULN) * aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤3x ULN if no demonstrable liver metastases, or otherwise ≤5x ULN if transaminase elevation is attributable to liver metastases * Total bilirubin ≤1.5x ULN, except for patients with Gilbert's syndrome: total bilirubin ≤3.0x ULN or direct bilirubin ≤1.5x ULN * Partial thromboplastin time (PTT)/activated partial thromboplastin time (aPTT) \