Complex sentence: In the first months of his presidency, Trump reversed several policies of former President Barack Obama, withdrawing the United States from the Trans-Pacific Partnership and the Paris Climate Agreement, and undoing parts of the Cuban Thaw.
Split into simpler sentences: In the first months of his presidency, Trump reversed several policies of former President Barack Obama. He withdrew the United States from the Trans-Pacific Partnership and the Paris Climate Agreement, and he undid parts of the Cuban Thaw.