Trump doesn't care, and wants it left to the states. Sessions thinks pot is a scourge and incredibly dangerous to society.
It's easy to say that Trump prevails, because he's the President, but he might not care so much that he just leaves it to Sessions.
I think illegal immigration is much higher on sessions priority list too. But we will see. If you are convinced they will go hard after marijuana then you are. One of the things you see about trump is that most of the time when he says "leave it to the states" it is code for "I dont care about the issue dont bother me with it"