Additional Study Information: The purpose of this study is to test the safety of the investigational drug, RP-6306, RP-3500, and Debio 0123. This study will test the investigational drug, RP-6306, alone or in combination with RP-3500 or Debio 0123, for the first time in humans. Investigational means that the study drug being tested has not been approved by the United States Food and Drug Administration (FDA). RP- 6306 is a PKMYT1 inhibitor (blocks the activity of the PKMYT1 protein), RP-3500 is an ATR inhibitor (blocks the activity of the ATR rotein), and Debio 0123 is a WEE1 inhibitor ((blocks the activity of the WEE1 protein). All three study drugs are designed to stop certain cancer cells from growing. You are being asked to participate in this study because you have an advanced cancer with a specific genetic change that is predicted to be sensitive to the study drug.