Looks like a fifth Indiana Jones movie is being planned. Actor Shia Labeouf hinted at Indiana Jones 5 during an interview given to the BBC (here):
“Steven Spielberg just said that he cracked the story on it before I left and I think they’re gearing that up.”
Actor Shia Labeouf
I suppose that this Indiana Jones 5 movie would focus more on Shia Labeouf, the previous movie clearly made him the legitimate heir to Harrison Ford.