Donald Trump is drawing praise and criticism for his out-of-the-box choice for secretary of state, Rex Tillerson.

As the CEO of oil giant ExxonMobil, Tillerson has had to make deals with some of the world’s most notorious leaders, including Russia’s Vladimir Putin. Some of Tillerson’s fiercest critics are Senate Republicans, such as Marco Rubio, who will question Tillerson during his confirmation hearing before the Foreign Relations Committee.

Tillerson has his supporters, too. Former Defense Secretary and CIA Director Robert Gates called him a man of “great integrity” with “vast knowledge, experience and success in dealing with dozens of governments and leaders.”

An Eagle Scout who is still involved in the leadership of the Boy Scouts of America, Tillerson worked his way from bottom to top at ExxonMobile. He’s known no other employer and will be the first to jump from corporate America to top U.S. diplomat with no prior political or government experience.

If he’s confirmed by the Senate