That's a big no no for the billionaire internet guy. According to a very well written investigative piece in a New York magazine, iCahn secretly spent his time in Trump's cabinet trying to lobby for a particular piece of regulation being removed. That regulation, uh, actually deeply changed the way a particular business for ICahn was actually ran.
The story printed by The Newyorker paints a picture of an ICahn who secretly tried to use his federal executive role to "furnish and benefit on his own good". That part right there, uh, is actually against federal law in the United States. In the United States it is against the law to try and influence federal regulations to benefit a business in a financial manner.
Which is what ICahn did.
The New Yorker expose reportedly uncovered ...