Sigvotatug Vedotin

The purpose of the study is to compare how the new combination treatment (Sigvotatug Vedotin plus pembrolizumab) works compared to pembrolizumab alone in patients with non-small cell lung cancer (NSCLC) with high levels of PD-L1. This is a protein that acts as a kind of "brake" to keep the body's immune responses under control. The study is seeking for participants who: * Are confirmed to have NSCLC (Stage 3 or 4). * Have PD-L1 levels in more than 50% of the cancer cells. All participants in this study will receive pembrolizumab at the study clinic once every 6 weeks as an intravenous (IV) infusion (give directly into a vein). In addition, half of the participants will also receive Sigvotatug Vedotin once every 2 weeks as an IV infusion in addition to receiving pembrolizumab. Participants may receive pembrolizumab for up to about two years. Those participants taking Sigvotatug Vedotin can continue until their NSCLC is no longer responding. The study team will monitorsee how each participant is doing with the study treatment during regular visits at the clinic.

This study is being done to learn more about a new medicine called PF-08634404 and how it works when used with other cancer medicines in people who have advanced solid tumors. An advanced solid tumor is a type of cancer that has spread beyond its original location and cannot be removed by surgery or cured with standard treatments. To join in the study, participants must: * Be 18 years or older * Participants with advanced non-small cell lung cancer (NSCLC), a type of lung cancer that has spread The study will look at: * Whether PF-08634404 is safe to use with other cancer medicines. * What side effects may happen. A side effect is anything the medicine does to your body that is not part of treating your disease. * Whether the combination of PF-08634404 and other cancer medicines can help treat solid tumors. The study has different parts, each testing PF-08634404 with a different cancer medicine: * Part A will test PF-08634404 with a medicine called sigvotatug vedotin. * Part B of the study will look at how well the new medicine PF-08634404 works when used together with another medicine. Participants will receive the study medicines through an intravenous (IV) infusion (injected into the vein) at the study clinic. All treatments will take place at clinical trial sites, where trained medical staff will monitor participants during and after each visit.