Jakku is the desert wasteland that is home to scavengers who make their living selling parts from old Imperial and Rebel vehicles and ships that have crashed onto the planet. It is featured in the first part of the Force Awakens and is home to Rey, the mysterious loner who is extremely strong in the Force.
The movie goes out of its way multiple times to point out how this is basically a crap hole of a planet that no one would ever want to live on. So why is such a horrible, desolate planet so vital to the Star Wars saga? Why was there a huge battle over this backwater planet?
There seems to be something to this planet that hasn’t been explained in the films. In Chuck Wendig’s Aftermath Trilogy it is explained that Palpatine had some testing facilities there and it could be an explanation for Rey’s existence if she were the product of these tests.
Maybe there is still something valuable on this planet that Rey or Kylo Ren need to get in order to defeat the resurrected Emperor. Or maybe this is where Rey goes back to at the end of the film. Who really knows? But it does feel like we haven’t seen the last of this dry wasteland and it’s reappearance in The Rise of Skywalker seems imminent.