Jyn Erso
Seeing as a younger version of Saw Gerrera is being included in the game, we may also see a younger version of Jyn Erso, as well.
As we saw in Rogue One: A Star Wars Story, Jyn was raised by Saw after her mother was killed and her father was taken by force to help the Empire to construct the Death Star.
We know from the movie that a young Jyn was member of the Partisans, which is also referred to as Saw Gerrera’s militia, until she was abandoned by the group when she was sixteen, after which she went out on her own, leading to the events Rogue One.
While it is unknown exactly how long after Order 66 that the game takes place, it is known that it is several years following the order. What is known for certain is that Jyn was adopted by Saw 6 years following the Order, so if the game takes place after then, then it is entirely possible that she appears as a member of his militia.
This likely would not be in a major role, and would likely only be a cameo for a character, but it would be a nice easter egg to be included in the game, and would also give the character of Jyn Erso more exposure, as she to this point, she has only appeared in one major movie.