I drove through northwest Louisiana last week - lots of Trump signs and even interstate-facing billboards. Not official campaign efforts, but local grassroots support stuff. Plus, I've heard that Johnson's district is going to have a chunk carved out of by the state, taking the city of Shreveport (or a significant portion thereof) into a new majority-black district. Mike's district isn't going away, though - it's just going to get redder.
I think he's going to get mauled by his voting constituents, next time he's up for reelection.