LGG

The purpose of this clinical trial is to learn the safety and effects of the study medicine (PF-07799544) alone or in combination as a potential cancer treatment for adults with advanced solid tumors. The study will be conducted in two parts: PF-07799544 as a single agent (Phase 1a) and PF-07799544 in combination with another study medicine called PF-07799933 (Phase 1b). Phase 1a is no longer open for enrollment. In Phase1b (noted as "this study"), we are seeking participants who have: * a solid tumor which is metastatic or recurrent (excluding colorectal cancer) * tumor with the mutation (abnormal gene) called "BRAF V600" * received required prior treatment for cancer per cohort assigned. All participants in this study will receive both study medicines. Both study medicines are tablets that are taken by mouth at home twice a day. Participants will receive study medicines until their cancer is no longer responding, unacceptable side effects, or 2 years. Participants may continue to receive study therapy beyond 2 years. We will examine the experiences of people receiving the study medicines. This will help us determine if the study medicines are safe and effective.

The objective of this Master Protocol is to evaluate the efficacy and safety of plixorafenib in participants with locally advanced or metastatic solid tumors, or recurrent or progressive primary central nervous system (CNS) tumors harboring BRAF fusions, or in participants with rare BRAF V600-mutated solid tumors, melanoma, thyroid, or recurrent primary CNS tumors.