For those curious on how you unlock things when switching between campaign and skirmish.
Now this also only applies to the host in campaign, any others joining will carry over Skirmish upgrades. During your campaign you will have research that unlocks basically any upgrades to your executor. This includes new classes, weapons, modules, skills, etc. These are not affected by your player level or upgrades from Skirmish (the exception being your combat suit upgrades and squad upgrades.)
Thats about it really.
While playing, you’ll probably notice you are accruing skill points while playing Campaign and Skirmish. These can be spent on the expanded skill tree outside of Campaign (or on combat suit and squad upgrades in campaign as well). These are permanent unlocks that allow you to use classes, weapons, modules, and skills in skirmish or as a co-op partner. You can respec, but there isn’t a level cap and it costs you XP to do. So I would just pick a class and stick with it till you get enough points to branch out. So essentially, as long as you aren’t hosting a campaign session, you are always gaining progress on new unlocks.
Unless the devs implement some changes, this will probably stay accurate. If they do change how things work, or add better explanations in game for players to easily find, then I’ll probably delete this guide as it will be redundant. I just hope this helped to explain these systems for any confused players.