This story does not start with developer Guerrilla Games, it starts with Star Wars. While speaking with fans at Star Wars Celebration, voice actress Janina Gavinkar let slip the existence of Horizon Zero Dawn 2, teasing "it's incredible". But the actress was on location at Star Wars Celebration due to her inclusion of that franchise too.
This is far from official confirmation that Horizon Zero Dawn 2 is on the way of course, though it does seem plausible that Gavankar would be back to voice her character.
Horizon Zero Dawn's sequel has finally surfaced on the web with some bits of information regarding the sequel. Luckily, the footage has been posted on Streamable, where you can watch for yourself. But it begs the question: what secrets could she be talking about?
Future of Horizon: Zero DawnHorizon Zero Dawn 2: Should we wait for its sequel?
Also, we need to rule out that the possibility that she could pbe playing another character in HZD 2, but we'll get news later on when the game actually comes out.
Horizon Zero Dawn has been a huge hit with PS4 gamers since its launch in 2017, and while a sequel has yet to be officially announced, a follow-up appears to be in development.
So, while it could be a little obvious, we know quite for sure that the game is in the making and perhaps has been for a relatively long while.