Infinity Ward won’t be following Treyarch’s footsteps by putting branching paths into Ghosts’ missions. Instead, Ghosts’ missions will contain ‘easter eggs’, that should you find will open up secret areas/events for you.
Talking to OPM, Infinity Ward’s Mark Rubin explained how the mission structure would work: “We don’t have the same branching system [Treyarch] do, obviously. But there is basically this way that, when you are in a mission, you might find something, if you grab it, then something opens up later in a different mission, or something happens later in that mission, that wouldn’t have happened if you didn’t do them”.
Rubin explained that the special objects players will need to be on the lookout for would be items that crop up “several times throughout the whole campaign”. It’s not hard to come to the conclusion that this will probably be things like intel, which by picking up will inform your army man of places he can go later on to get better equipment or the like.