oxaliplatin

This study is being done to find out if tucatinib with other cancer drugs works better than standard of care to treat participants with HER2 positive colorectal cancer. This study will also determine what side effects happen when participants take this combination of drugs. A side effect is anything a drug does to the body besides treating your disease. Participants in this study have colorectal cancer that has spread through the body (metastatic) and/or cannot be removed with surgery (unresectable). Participants will be assigned randomly to the tucatinib group or standard of care group. The tucatinib group will get tucatinib, trastuzumab, and mFOLFOX6. The standard of care group will get either: * mFOLFOX6 alone, * mFOLFOX6 with bevacizumab, or * mFOLFOX6 with cetuximab mFOLFOX6 is a combination of multiple drugs. All of the drugs given in this study are used to treat this type of cancer.

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.