Advanced Colorectal Cancer (Part 1)

The purpose of this clinical trial is to learn about the safety and effects of the study medicine (called PF-07799933) administered as a single agent and in combination with other study medicines in people with solid tumors. This study is seeking participants who have an advanced solid tumor with a certain type of abnormal gene called "BRAF" and available treatments are no longer effective in controlling their cancer. All participants in this study will receive PF-07799933. PF-07799933 comes as a tablet to take by mouth, 2 times a day. Depending on the part of the study, participants may also receive another study medicine: * People with melanoma or other solid tumors may also receive binimetinib. Binimetinib comes as a tablet to take by mouth, 2 times a day. * People with colorectal cancer may also receive cetuximab or cetuximab and mFOLFOX6 (Chemotherapy regimen). Cetuximab will be given weekly (or every two weeks) in the clinic as a shot given in the vein or port (intravenous, IV). Participants may receive the study medicines for about 2 years. The study team will monitor how each participant is doing with the study treatment during regular visits at the study clinic.