**Study of XB010 in Subjects With Solid Tumors** This study is for adults with solid tumors (cancers that form in solid organs or tissues). The goal is to see how safe and effective a new drug called **XB010** is, both alone and with another drug, **pembrolizumab**. This study has two parts: **Dose-Escalation** and **Cohort-Expansion**. In Dose-Escalation, researchers find the best dose of XB010. In Cohort-Expansion, they study XB010's effects on specific types of tumors. **Key Points:** - **Commitment:** Participants must be 18 or older and able to follow study rules. - **Duration:** The study involves multiple stages, with no specific end date mentioned. - **Health Check:** Participants need to have a confirmed solid tumor and be in good general health. If you're interested, you'll learn more about risks and benefits, and you'll need to sign a consent form. This study is for those who have limited treatment options. Participation in the study may involve different types of tests and visits to the doctor.