This page of the Dying Light 2 game guide answers whether crossplay is available.
Crossplay at launch
Crossplay won't be available upon launch. We won't know until after the release if the developers will attempt to add this feature to their title.
Consequently, you will only be able to beat 100% of the game with a companion who has the game on the same platform. It's worth keeping in mind that, in some cases, you might be required to purchase an additional service, such as PS Plus.
The PC version purchased from the Microsoft Store and the Xbox version might be an exception. In the case of these two, it's possible to play together on different platforms.
It is worth noting that Dying Light 2 was released on:
- Nintendo Switch.