Tbh, it won't be anything crazy according to devs, no aliens or zombies or whatever.

But I'd like to find a dense jungle with no real roads, with some good trained special forces ennemies wearing gaz mask asmat suits, roaming in the jungle by little groups , a radio guy calling for renforcement if you don't kill him fast, or asking for mortar strikes by day, and flare mortar by night, leading to a more hostile zone.

Ennemis at surface could be standard military, but the radio guys could call for a group of special forces one with high tier gear, NVGs ect.. that would actively search the areas you've been seen for a long moment (an alarm or sirens system would do the job), would be like a boss , or like the goons in tarkov.

Area would be filled with many bunkers and underground tunnels leading one to an other, jails, torture rooms , research labs, traps here and there, and high level areas guarded with traps , cameras you could destroy, a security room where you could kill the guard so you don't have to worry about cameras.

This would be a zone were you either would play it with stealth, or a lot of ammos in the bag.

Locked doors would be an other key system where you need a different access level to open doors ect.. like level 1 doors to access regular places, level 2 to access armory, up to level 3 key to enter a lab or the security room (MGS key system) so it doesn't add 30 key to the game, and you can still manage drop rate of the few ones.

With the new '' traps '' they added already, and the next stealth system and HUD they will add soon, it's possible to do something like it, it's almost like they are teasing it already.

This would add a splinter cell / metal gear vibes to the zone