again, I highly doubt there will be a sequel, I think there will just be DLCS and expansion packs or a sequel story in the same game kinda like hl2 episode 1
Whatever this "major global IP" game is, which is where these rumors are centered on (speculations and "leaks"), I'm sure it will be revealed what exactly it is for the 2020 Gamescom (digital) event, since that's coming up in less than three weeks from now, because that's where Frontier usually showcases their newly upcoming games,
and they are on this year's Gamescom event list. But, I know it won't be the only thing they will be showcasing there, as there are a couple of other major things of theirs coming up for two of their current games.
However, it should also be taken into consideration that "the game" (as they call it as of now) may be announced at least a few days or so before the event starts, because
Jurassic World Evolution, the other game based on a major global (or Hollywood) IP accordingly to their contract with Universal,
was first announced
two days before the start of the 2017 Gamescom event where it was announced much further.
So, whatever it is, these rumors will all be over soon,
"hopefully" around the Gamescom week, before or during the event running days.