First of all it needs to be said that these might not be a 100% accurate but the cases show us what the Galaxy S8 might look like.
On the picture above we see new alleged cases of the Samsung Galaxy S8 and S8 Plus. I’m not quite sure yet if those are official Samsung cases or made from third parties, but we still get quite a good look at what the Galaxy S8 might look like from the back. We can see those 2 holes in the back which will be for fingerprint reader and the camera setup, as well as maybe the heart rate monitor. The new placement of the fingerprint sensor might be unconvenient for those with a bit larger hands, since there’s always a chance of smudging the camera
When looked at from the front , we can see that there is a big space for buttons on the left side, presumably for volume keys and the lock key, but also a button on the right hand side. This button is positioned to high to be a dedicated camera key, so it’s safe to say that this might be a dedicated AI button to start samsung’s own take at Siri, Cortana and so on, called Bixby.
Again all of those are just rumors and assumptions, so for anything real we need to wait for the official announcement.