Back in March, we ran a little feature on Carolina Ravassa, the voice actor behind Sombra who spent a day cosplaying as the Overwatch hacker. That was at Katsucon, but for BlizzCon 2019, she was joined by two other cast members, Anjali Bhimani (Symmetra) and Matthew Mercer (McCree).
Source: Kotaku – Overwatch Voice Actors Hit BlizzCon Cosplaying As Their Characters