Spoiler alert: if you haven't played the game, it may be a good idea not to read the news. You have been warned.
The story of The Last of Us: Part II is a dark one. Like really dark. It was so dark, that even a petition was made to change the story. But actually, the original ending was supposed to be even darker.
As reported by GameSpot, The Last of Us Part II's creative director Neil Druckmann and narrative lead Halley Gross appeared in Game Informer's podcast stating, that originally Ellie was supposed to kill Abby. In the end, the team decided that it would be too dark and grim, so they decided to let Abby live. There is still some humanity left in Ellie after all.
"We did a lot of iterations on what that last act looked like, but the final beat was that Ellie would kill Abby. About halfway through production, we changed that and had Ellie let go at the last second to [illustrate] that some little part of the old Ellie, the Ellie with humanity, the Ellie that is impacted by Joel, still exists within this character who has been so overtaken by her quest for revenge."
The story of The Last of Us: Part II seems to be finished, because there are no plans for DLC. You can read our review about the game right here.