Judging from Blizzard's actions in recent years, the new end game is expected to be launched within three years, because Blizzard said that the game has been quietly developed for 4 years. The reason why it has not been announced is mainly that Blizzard has been criticizing things in the past two years, from the Dark Immortal Finale Carnival, to the plummeting reputation of the Warcraft 3 remake, to the sexism and sexual harassment incident that broke out last year.
It can be said that Blizzard's reputation plummeted all the way, with only 26 million monthly active users remaining. But Blizzard has done two positive things this year, one is that it is wholly owned by Microsoft, and the other is this unnamed terminal game.
Blizzard also released an official announcement on the official website, and is currently recruiting a development team for this game, for details, you can see the following figure.
