10 Video Games That Made You Work Out The Answer Yourself
6. The Last Of Us
The Question: Is Ellie the only immune human on Earth?
In both Last of Us games, protagonist Ellie is the only person immune to the Cordyceps brain infection that we ever see.
It's made clear that immune people are at least enough of a rarity that the Fireflies are desperate to experiment upon Ellie in the hope of reverse-engineering a vaccine.
Though the lack of other immune individuals might suggest Ellie to be the only one, it's also totally reasonable that other immune people would conceal their status for fear of reprisals.
Plus, despite the human population dwindling significantly, there are presumably still a lot of people around the globe who could conceivably be immune, and accepting how real infections work, it's basically a mathematical impossibility that Ellie is the only immune person on Earth left alive.
If a third Last of Us happens, which it probably will eventually, there's a solid chance it might clear up this mystery once and for all.