Legally, a president is not covered by conflict of interest laws like members of Congress are

However,  gifts are a really big problem and might get Trump impeached. So, this is something for the Trump Administration to think about. However, it is the impropriety of (how this looks to Americans and to the world) that will tend to corrupt the world's perception of this president and give the world the impression that he is a Third World Banana Republic like President.

The problem is there are millions of ways (literally) since he has 500 businesses that he either owns outright or is invested in that could be doorways for (Gifts) (which are normal in most countries) which would cause his impeachment quite easily here in the U.S. because of existing laws regarding U.S. Presidents.