President-elect Donald Trump has tapped Exxon CEO Rex Tillerson for the role of secretary of state. Trump said on Twitter Monday night that he will make an announcement on the role Tuesday morning. The Tillerson choice puts an end to what was a lengthy search for Trump, featuring candidates like Rudy Giuliani and Mitt Romney. Tillerson has spent the past four decades at Exxon where he secured oil and gas agreements in troubled parts of the world.