A Study to Learn About the Study Medicine Called PF-08098488 in People With Advanced Solid Tumors.

The purpose of this clinical study is to learn about the safety and effects of the study medicine (called PF-08098488) in people with advanced solid tumors (cancer that cannot be removed with surgery or has spread to other parts of the body). PF-08098488 is being studied as a possible treatment for certain types of cancer. These include non-small cell lung cancer, pancreatic cancer, stomach or gastroesophageal junction cancer, and esophageal cancer. This study will also help researchers learn how the study medicine moves through and affects the body. This study is seeking adults who: * Have advanced non-small cell lung cancer, pancreatic cancer, stomach or gastroesophageal junction cancer, or esophageal cancer. * Have received at least 1 previous treatment for their cancer. * Have cancer that has grown, returned, or is no longer responding to available treatments. All participants in this study will receive PF-08098488 as an IV infusion (given directly into a vein) at the study clinic. Researchers will study different dose levels and dosing schedules to find the dose that is safe and may work best. Participants will be monitored closely during treatment, especially after their first infusion. They may continue receiving the study medicine as long as their cancer is not getting worse and they are tolerating treatment. The study includes a screening period of up to 28 days. Participants will have regular visits to the study clinic for treatment and health assessments. These assessments include scans to monitor the cancer and blood sample collection. Tumor tissue samples will also be collected when available or medically feasible. After treatment ends, participants will have a follow-up visit about 1 month later. They will then be contacted about every 12 weeks to check on their health.