5 things to know about Exxon Mobil CEO Rex Tillerson, Trump's likely secretary of state

News broke Saturday that Republican President-elect Donald Trump has chosen his future secretary of state: Exxon Mobil CEO Rex Tillerson.

As the leader of the world's largest publicly traded oil company, Tillerson certainly has management experience. Diplomatic experience? Well, not really. Here's what you need to know about Trump's latest cabinet pick.

1. Tillerson has no public sector experience.

Tillerson at an Abu Dhabi oil conferenceJon Gambrell/AP

Tillerson is a career company man. He first joined Exxon in 1975 as a production engineer and gradually climbed the corporate ladder to become CEO in 2006.

He is also, however, a trustee for the Center for Strategic and International Studies, a centrist think tank.

Tillerson's net worth is in the hundreds of millions, meaning he would be the latest in a growing line of multi-millionaires and billionaires to join Trump's cabinet or serve him as an adviser.

2. Tillerson has close ties to Russia, which the CIA now says tried to manipulate the election for Trump.

Exxon Mobil "explores for oil and gas on six of the world's seven continents and has operations in more than 50 countries," according to the Wall Street Journal; one of those countries is Vladimir Putin's Russian Federation. Tillerson negotiated a major deal in 2011 giving the oil giant access to Russia's Arctic oil reserves in exchange for allowing Russia's state oil firm, OAO Rosneft, to invest in Exxon Mobil operations around the planet.

While the deal earned Tillerson an Order of Friendship medal from Russia, it was subsequently blocked by sanctions imposed by the U.S. and its allies "after the country's invasion of Crimea and conflicts with Ukraine," according to the Journal. Tillerson was an adamant opponent of the sanctions.

"Friends and associates said few U.S. citizens are closer to Mr. Putin than Mr. Tillerson, who has known Mr. Putin since he represented Exxon's interests in Russia during the regime of Boris Yeltsin," the Journal wrote.

Tillerson's ties to Russia are bound to be a matter of concern in the coming weeks, as the CIA recently announced it believes Russian actors "one step" removed from the Kremlin deliberately interfered with the 2016 presidential elections to throw them for Trump. Several prominent Republican senators, including South Carolina's Lindsey Graham and Arizona's John McCain, have expressed alarm about the Russian operation, which could easily complicate Tillerson's eventual cabinet confirmation hearings.

3. Tillerson's stake in Exxon constitutes a potential conflict of interest.

Tillerson at a press conference in 2006LM OTERO/AP

Becoming secretary of state could be a huge boon to Tillerson's wallet.

As CNBC's Steve Kopack noted, Tillerson owns some $233 million in Exxon Mobil shares — all of which he can divest tax-free by obtaining a certificate from the Office of Government Ethics. While Tillerson would have to pay capital gains taxes on the new assets he receives in exchange at a later date, the move would allow him to defer taxes, and possibly pay a lower rate if the Republican-led Congress decides to cut those taxes.

As the Wall Street Journal also noted, the value of Tillerson's shares could spike if the sanctions on Russia are lifted.

4. Tillerson believes in climate change — but has bad blood with environmental activists.

An Exxon storage facility fire in Staten Island in 2003Adam Rountree/Getty Images

Unsurprisingly for the head of a company concerned with pumping oil — and which initially denied climate change after becoming aware of it in 1977 — Tillerson has a long history of conflict with environmental activists. Under Tillerson's tenure, Exxon Mobil paid huge sums of cash to groups like the American Legislative Exchange Council, which promotes unscientific views on climate change; the corporation has paid out tens of millions to muddy the public's view of a changing climate as a threat to human civilization.

Somewhat more surprisingly, his views on the issue may be to the left of Trump's, as the CEO shifted Exxon Mobil policy in 2006 to acknowledge climate change as a general concern and endorsed a carbon tax as the best policy response.

This could come into play during negotiations over international treaties and agreements on the climate. Trump firmly opposes agreements like the Paris Agreement and has threatened to pull the U.S. out of it entirely. The apparent conflict between the two men's views could push Trump to the left on the issue — or it could come to nothing.

"This is certainly a good way to make clear exactly who'll be running the government in a Trump administration — just cut out the middleman and hand it directly to the fossil-fuel industry," climate activist Bill McKibben told the Journal.

5. His views on other issues are largely a mystery.

As the Washington Post noted, other than his passion for oil, his pro-Russia bend, his views on the climate, his support for free trade agreements and a general alignment with Republican party principles, Tillerson's opinions on the global issues of today remain a wild card.

While that might be somewhat of a relief for progressives compared to known hawks like former George W. Bush administration official John Bolton, the prospect of a secretary of state without a record of government service and whose views on international policy remain largely unknown is also disconcerting. As secretary of state, Tillerson would be the government's lead official for dealing with geopolitical issues including a newly expansionist Russia, the raging civil war in Syria and Trump's frequent tirades against countries like Mexico and China.