From all I can recall, both movies were to be called Avatar, but there was an obvious dispute. I think M. Knight's is based on source material called "Avatar," so it's a shame he apparently lost out on the right to use it.
So the stories are completely different, at least that's what I remember from the dust-up of the movie names from many, many months ago. I'm not familiar with either story.
But the
trailer for the Cameron movie "Avatar" looks nothing short of awesome + rad.
(
That would be radsome, but it sounds like a cheap hotel chain)