Aliens: Fireteam Elite has four chapters with three missions each, for a total of 12. At the end of the first deployment for any chapter, you can select to move on to the second once you’ve completed it.
You don’t have to return to the Endeavor or exit the campaign menu. The same goes for the second mission. If you do want to exit, you can just return to the campaign menu, select the chapter, and go from there.
However, there’s a slight wrinkle after completing the third operation of any chapter (except for the very last one in the game).
After completing the third mission in any chapter, you must return to the UAS Endeavor and speak with an NPC to unlock the next chapter. This NPC will have a blue box with an exclamation point above their head. Interact with them, exhaust the dialog, open the campaign menu, and the next chapter will be available. Just play through to unlock more.
Note: If you want to change your Loadout Kit, add weapon attachments, change your appearance, tweak perks, or purchase anything at all, you must return to the hub. You can’t change any anything between or during operations.
If you’re picking up all of the intel for CMISRS Asset along the way, the Endeavor will be full of NPC icons, so losing the blue one in the noise can happen. But now you know how to unlock campaign missions and chapters in Aliens: Fireteam Elite. For more, consider heading to our guides section for hidden cache location, how to save, and more.