This page of the Returnal guide informs if the game will be available for PC in the near future.
Returnal is a third-person action game developed by Housemarque with rogue-like elements, which is one of the few exclusive titles on the next-generation PS5 consoles. However, this doesn't mean that Returnal will never be released on PC, but there is currently no confirmed information about this.
It is possible that after the exclusivity period (usually a year after the release), Housemarque will decide to make their game available to more users and Returnal will be published on other platforms as well. In recent years, many PS4 exclusive titles have been ultimately published for PC, so it is possible that this trend can continue with the ninth console generation.