**Study Overview** This study tests a new drug called **BI-1910** in people with advanced solid tumors—types of cancer that start in organs or tissues like the liver or lungs. These tumors have worsened after standard treatments. The study will see if BI-1910 alone or with another drug, **pembrolizumab** (a cancer-fighting medicine), is safe and what dose works best. Participants will receive treatments every 3 weeks. **Key Points:** - **Length & Visits:** Participants will receive treatment infusions every 3 weeks. The study duration depends on individual responses. - **Eligibility:** Participants must be at least 18 years old with solid tumors that progressed after standard treatment. - **Risks & Safety:** The study will monitor for side effects to understand how safe the treatment is. This research involves two main phases. The first phase explores how much BI-1910 can be safely given, while the second phase checks if it works well to fight the cancer. Eligibility requires good general health and the ability to provide a tumor sample. People with certain medical conditions or recent cancer treatments may not be eligible. This study helps researchers learn more about new cancer treatments.