MiHoYo—the Genshin Impact developers—announced on the 7th of October that closed beta signups for their upcoming game have been opened. Honkai: Star Rail will be set in the same universe as Honkai Impact 3rd, and will be available for both mobile and PC.
The reveal trailer "Next stop, the Stars!" seems to feature gameplay very similar to Genshin Impact's, and they showcased several of the to-be playable characters and what appears to be their special abilities, along with the galactical setting the game will have.
Honkai: Star Rail's official site is up and taking signups for its first closed beta, and offers some information regarding the game, including characters, their backstory, and gameplay, with seemingly 8 different characters to select from in this beta period. It seems like MiHoYo intends to make Honkai: Star Rail have a similarly broad roster to choose from as Genshin Impact's.
Unlike Genshin Impact, it seems like Honkai: Star Rail will be a turn-based RPG with dungeon exploration where teams will be composed of four playable characters.
The signup period will run indefinitely until a future announcement of the exact end date. The closed beta will have a limited number of participants, and any progress made will be deleted once the early access period comes to a close.
The official FAQ dictates that there is no official start date for the closed beta, and it will release with support for Chinese, English, Korean, and Japanese.