There is certainly an irony to the fact that Luke disappears after giving in to the thing he’s been neglecting for so long.
This, combined with the fact that Mark Hamill is confirmed to appear in Star Wars: Episode IX would indicate that we’ll see Luke again as a Force Ghost or something similar.
One thing that the Star Wars: The Last Jedi does do is make it plain that Luke hasn’t simply died, but has joined “a larger world.”
He has become part of the Force in the same way that Ob-Wan Kenobi and Yoda have done before him.