It looks like Krafton, which includes the developers of the PUBG battle royale, is already engaged in sequels to both the main version of the title and the mobile one. This was announced by a PlayerIGN insider in a press release or internal document from November last year.
The game code name is ProjectXTRM.
According to the document, Krafton is making one generic version of PUBG 2 (of course, with technical differences depending on the platform), which, apparently, will receive crossplay and cross-progression between PCs, consoles and smartphones.
The media suggest that the announcement will take place in March this year.