If I am playing a game on PC, does everything transfer to Xbox when I play there

Mods cannot be used on Xbox, either PC or console

If you have the Steam version your save is isolated to that service. Only MS store versions are PlayAnywhere. Please keep in mind that any modifications you may make to the game may make your save incompatible or corrupt it.

It would depend on the game. Not all games support cross-saves.

I am thinking it has something to do with the problems they are having right now with profiles and downloads on the 360. It is not a file transfer or license transfer, as this is the same Xbox it was on before. I should be able to play, and so should anyone
else with a profile on the Xbox, be able to play the game downloaded thru his profile as the license is transferred to the Xbox 360, not the account like it is on the Xbox 1. I have done this in the past with other games. I just have not played on the 360
in a long time and cleaned a lot off of it when I stopped, such as Dark Souls, as I was playing the Xbox 1 I just got over the last Christmas holiday season and playing on the PC.

Hello

Steam is a separate Platform. It won't save to Xbox or transfer over. It does support cross play so you can be matched with people on console and PC when playing multiplayer.

Yes I know that. But If I am on "PC" and play Conan through game pass am I with PC players or Xbox?

You would be on with PC players given it's not cross-play. Whilst Game Pass does cover both PC and Xbox, you would only be on with those on similar versions so PC-to-PC, Xbox-to-Xbox etc