Can xbox and ps4 cross play with eachother for minecraft?

Sadly no, you can't

I regret to inform you that Sony has NOT GRANTED PERMISSION FOR CROSS-PLATFORM SUPPORT with Minecraft. Therefore, PS4 version is still on it's own "Legacy Edition" of Minecraft while XBox One, Switch & Mobile versions are running on the Bedrock Engine.

Once Sony decides to allow cross-platform multiplayer between the PS4 & other consoles, it'll get added to the Bedrock Engine so it'll be in-sync with all other platforms moving forward.