Windows 10 task bar is on top of full screen video or games.
This happened to me recently. I could not figure it out for a while, there are all sorts of "fixes" on the internet about it.
I got a clue that reminded me that I had changed the resolution of one of my monitors to something other than normal, and back again. restarting explorer did not fix the issue. I logged off and back on again and now it is back to normal.