I added this to my original posts, but wanted to call this out as I missed it earlier (i hadn't had enough coffee yet, please forgive me).
There are 2 additional features of Rebellion:
New In-Mission ObjectiveRandomly occurring during waves 3, 6 and 10, this new objective will demand that teams retrieve a high priority package and securely escort it to a designated extraction zone on each map.
New Gear SlotA new slot will be available on the equipment screen, offering players a persistent gameplay bonus that will not expire after the end of a match. These new items will vary from weapon upgrades to character enhancements and will be available through reinforcement packs.”