Even though nothing is official, it seems unlikely that The Last of Us 3 isn't somewhere on the horizon. While the game isn't confirmed to be in development at all, Neil Druckmann himself did confirm that a story outline has been written. It'll be a long way off, and Naughty Dog has a lot of other rumored projects going on that could be taking precedent over The Last of Us 3, but it's surely coming someday.
The Last of Us 2 left a lot of questions unanswered, particularly in regards to Ellie's ultimate fate. Players followed Ellie as she became obsessed with her need for revenge, unable to let it go and try to live a normal life. Ellie's violent actions and refusal to quit caused her to lose everything, from her family, to her ability to play the guitar in remembrance of Joel. Most of The Last of Us 2 was downhill for Ellie. With that said, it feels like fans have only seen the first half of Ellie's character arc; the next game could make it come full circle.
Dina Could Reconcile with Ellie - Or Not
One of the biggest questions fans had at the end of The Last of Us 2 was the sudden disappearance of Dina and baby JJ. Dina was devastated when Ellie left to pursue Abby and abandoned the picturesque life they made together, so it would make sense for Dina to no longer want that relationship. Ellie essentially chose Abby and her vengeance over Dina and JJ; even when factoring in the PTSD Ellie was clearly suffering from, that'll be a difficult relationship to mend.
The game leaves things between Ellie and Dina a bit ambiguous. A lot of fans don't think they're together anymore, and it would tie into the pattern of Ellie losing everything for the sake of her vengeance. Others have speculated that Ellie was just visiting the house on her own to pick up some things, and then would return to Dina later.
The main evidence supporting that theory is that Ellie doesn't look surprised when she enters the house. That could be because she knows where Dina is, but on the other hand, it could be because she knows Dina herself and isn't surprised that she left. Ellie knew what her choice would cost.
One way or another, Dina and JJ will have to be addressed in the continuation of Ellie's story, and what happens between them would set the tone for the next step in Ellie's journey. The Last of Us 3 could go a more hopeful route by showing Ellie and Dina reconcile and agree to continue raising JJ together, or it could see them forever estranged because of Ellie's decision.
Ellie Could Return to the Fireflies and Finish What She Started
Ellie was furious with Joel because of how he saved her from the Fireflies, and the cause of that anger is the immense survivor's guilt she feels. She watched Riley, Tess, Henry, Sam, and countless others die while she somehow survived — and that's before witnessing Joel's horrific end. Ellie's mission in finding the Fireflies was motivated by that guilt and by a desire for her life to mean something. In one of The Last of Us 2's final scenes, Ellie accuses Joel of stealing that from her.
Ellie believes that her life would have mattered if she'd been used to create a cure for the cordyceps brain infection, regardless of the cost. Now that she's seemingly lost everything, Ellie's journey could send her on a path to find the Fireflies again and finish the mission that she and Joel started in The Last of Us.
Dr. Anderson is dead, but if Ellie found out that the Fireflies were still around then she might seek them out. If not the Fireflies, she might catch wind of another group trying to find a cure and pay them a visit, desperate to make sure her life makes a difference.
There are lots of avenues the story could take that result in Ellie trying to sacrifice herself for the sake of humanity, but having her return to the long-lost faction is by far the most interesting possibility. Assuming, of course, that Abby and Lev managed to find the Fireflies themselves. Assuming Tommy is still hunting for Abby as well, paths could cross in some very interesting ways if the Firefly camp makes an appearance. And as a major symbol of The Last of Us series, it definitely should.
Ellie's The Last of Us 3 Arc Could Mirror Abby's
The ending of The Last of Us 2 saw Abby and Lev get on a boat and sail off, presumably to find the Fireflies. After spending half of the game with Abby and knowing she survived until the end, it would be a waste of two perfectly good characters to never have her and Lev show up again. If Abby, Lev, and Ellie all made it to the Fireflies, things could get very interesting in more ways than one. Whether or not Abby and Lev show up, though, Ellie's story could very easily parallel Abby's arc.
Ellie and Abby were presented as two sides of the same coin in The Last of Us 2. We meet Abby at the end of her revenge mission and then journey with her as she struggles with the consequences and seeks to redeem herself by helping Yara and Lev. Ellie's arc in The Last of Us 2 centers around her revenge mission. Abby starts at the bottom and works her way up the moral ladder, so to speak, while Ellie is trapped in a downward spiral for the duration of the game.
Ellie's story could continue with her going on a similar journey to Abby. Ellie has clearly reached rock bottom by the end of The Last of Us 2, but that means there's nowhere to go but up. Ellie committed some truly heinous acts that she'll likely want to redeem herself from. The Last of Us 3 could be Ellie's redemption story the way it was for Abby.
Ellie Needs to Find a New Purpose
Regardless of what form it takes, Ellie needs to somehow find something to keep fighting for. She believes that her life doesn't matter and doesn't make a difference, so The Last of Us 3 should explore Ellie learning to challenge that belief and let go of her survivor's guilt. Changing the world is not a requirement for leading a meaningful life, and if The Last of Us 3 ended with Ellie dying for the sake of the cure, that would be a huge letdown.
Ellie needs to find a new purpose in the next game. Like both Joel and Abby, maybe that involves finding someone to love and protect — that someone could be JJ, or maybe Ellie's new purpose could be helping Joel's brother Tommy let go of revenge and come to the same conclusion she did.
Whatever it is, she needs to learn that there are a lot of ways to make an impact on the world and very few of them involve self-sacrifice. Joel tells Ellie that no matter what, you keep finding something to fight for. If Ellie's story can continue from here, she needs to find her new something to fight for in The Last of Us 3.
The Last of Us 2 is available now on PS4.