If you want to know the difference between an Overwatch fan and a member of the Overwatch fandom, ask them which characters are LGBTQ+.
Attentive fans will likely know that Tracer has a girlfriend, Emily, based on a dialogue line she has on a single map and a comic released separately from the game. It’s less likely, but possible, that they will have seen the Tweet from lead writer Michael Chu and know she was confirmed to be a lesbian specifically.
Ask a member of the fandom and they’ll probably have a list. Pharah and Mercy are usually dating, as are Hanzo and McCree. They might eschew Emily to imagine Tracer in a relationship with any of the other women in the game, though usually Widowmaker. Lúcio, Junkrat, McCree, Genji, and D.Va are all commonly imagined to be transgender.