Call of Duty: Black Ops 3 campaign is different than other Call of Duty titles. According to a video from Drift0r, the game timeframe doesn’t jump around a lot – you play the story within weeks of all the events taking place.
After every mission, you have the ability to return to The SafeHouse. The Safehouse is the place where you are able to customize your character, design your sleeping quarters, upgrade and personalize your weapons, a gun rank to see all your weapons, all your medals listed, and more. This is the one place that your team in the game returns too before starting the next mission.
Now, it’s not clear if Safehouse will be present in multiplayer…we’ll update as learn more.