I'm done with Metal Gear Survive's campaign and at this point I'm basically waiting for matchmaking sessions to actually fill, but Konami says that more content is on the way -- which could spur more people into action after they've finished the campaign in turn.
Starting next month Konami is adding post-launch content, which includes the new mission type "Rescue." As expected you'll need to brave the enemy and rescue NPCs, and all of this will be happening in tandem with new modifiers for challenges that alter the way you approach each mission.
I really hope other sweeping changes are in the pipeline, like the complete eradication of microtransactions and some other tweaks to the tedious survival formula.
via destructoid https://www.destructoid.com/metal-gear-survive-is-getting-post-launch-content-in-the-form-of-co-op-missions-491711.phtml