A Study to Learn About the Study Medicine Called PF-08165784 in People With PIK3CA-Mutated Advanced or Metastatic Solid Tumors

The purpose of this study is to learn about the safety and effects of the study medicine (called PF-08165784) when given alone or together with other anti-cancer therapies. Anti-cancer therapy is a type of treatment given to stop the growth of cancer. This study also aims to find the best amount of study medication that can be given to patients. This study is seeking participants with a specific type of breast cancer (BC) called hormone receptor-positive (HR+), HER2- negative (HER2-) breast cancer, or colorectal cancer (CRC) (cancer of the colon or rectum), that has a change (mutation) in a gene called PIK3CA. The cancer must be advanced or metastatic, meaning it has spread to other parts of the body or cannot be completely removed with surgery. All participants in this study will take the study medication (PF-08165784) as a tablet by mouth. The participant may take the medicine at the study clinic during study visits or at home. Treatment will be given in 28-day cycles and will continue for as long as the participant remains in the study. Depending on which part of the study participants are enrolled into, they will receive the study medication (PF-08165784) alone or in combination with other anti-cancer medications.