This study is testing a new drug called MCLA-158 for people with advanced solid tumors, like some types of cancer. A solid tumor is a mass of cancer cells that form in organs or tissues. The study has two parts: the first part has figured out the best dose, and the second part is checking how well this dose works. The study will look at the drug's safety, how the body processes it (pharmacokinetics or PK), and any effects it might have on the immune system.

Key Points:

• The study is being conducted at multiple centers and is open to patients with certain types of cancer.
• Participants may receive MCLA-158 alone or with other therapies, like chemotherapy.
• Participants must meet specific health criteria to join, such as having a life expectancy of at least 12 weeks.

People interested in the study should know it involves regular treatments every two weeks. They will also be monitored closely for any side effects. The study hopes to find out if MCLA-158 can help stop cancer from growing. Participation is voluntary, and all candidates must meet certain health requirements to join.