We are eagerly awaiting the third game of The Last of Us franchise, and it will be a while before we see more of Ellie. To cope with the indefinite release window, fans of the games have come up with theories about what Part III would be about, and some of them are actually compelling.
1. The Fireflies Might Attack Jackson
It was the Fireflies who attempted to make a vaccine by reverse-engineering Ellie's immunity, but was unsuccessful due to Joel's intervention. Considering that Abby survived, she might've returned to the rebel organization and let slip that Ellie was alive and knew where she was.
This could serve as a lead for the Fireflies, which they haven't had since Joel drove off with Ellie from the hospital. Reddit user @ZiangoRex theorized that the group might come to Jackson and attack the town to retrieve Ellie. This will eventually reveal that Tommy knew all along and kept it from them.
As a result, the town would be divided with some believing that the secrecy is justified, while the others would think that the secret is what got them in the mess and disrupted the peace. This could lead to some leaving, thinking that they are no longer safe in Jackson.
2. Ellie Would Be Generally Hunted
Building on the first given theory, more people would know about Ellie's immunity. There's a reason that Joel thought it was best to keep it a secret. It was either people would just kill Ellie out of fear, or she would be kidnapped to be sold to the highest bidder, as per @Hoshi_Reed.
This could make life for Ellie much harder than it already was if the secret spreads. Staying in Jackson might mean that she will endanger all its residents, and running away will expose her to not only the Infected but also people who want to exploit her immunity.
Everyone would want a vaccine, of course, and anyone who manages to create one will hold a lot of power once they do. That means that FEDRA and the Fireflies will actively hunt Ellie, along with others who were hired in exchange for resources.
3. Dina and Ellie Reconciles
Several theories are floating about The Last of Us Part II stating that when Ellie went back to the empty farm, she had already gone back to Jackson. There were many indications that a lot of time had passed since she let Abby go, such as her hair had grown, and her fingers having healed.
Redditor @Helloneighborfanpage mentioned that Ellie was wearing Dina's bracelet during the cutscene, which she wasn't the entire time she was hunting Abby. She might've only returned to the farmhouse to retrieve Joel's guitar, but eventually left it as a symbol for letting Joel go.
Ellie heading back to Jackson and seeing Dina again might not have been all sunshine and daisies. Of course, there might be some resentment since Ellie chose revenge over Dina and JJ, but The Last of Us Part III might include scenes where Dina forgives Ellie.
4. Ellie Sees She's Worth More Than Her Immunity
With all the chaos surrounding Ellie's immunity to Cordyceps, she finally realizes that she is more than that part of herself. Some fans say that she could sacrifice herself, but this was disputed as it would mean that Joel died in vain, as pointed out by @dospaquetes.
After all, Joel killed the doctor, Abby's father, to save Ellie, and Abby then killed Joel for revenge. It aligns with other fan theories as well, which say that Joel believes Ellie's death would not be worth saving the humans that were left.
