You'll be able to add both the French and Russian armies to your campaign when you pick up the Premium Pass in addition to the first DLC pack, called They Shall Not Pass. Premium Pass owners will be given two-week early access to each DLC package, beginning with They Shall Not Pass, which is scheduled for release in March 2017.
In addition, the pass offers 16 new multiplayer maps, new Operations and game modes, Elite classes, 20 new weapons and a slew of new vehicles to mess about with. Battlefield's Battlepacks are making a return as well, which will be delivered each month beginning November 2016. If you're a collector, you'll want to check out the 14 new dog tags that'll be released over the Premium Pass season period.
Battlefield 1 hits Xbox One, PC and PlayStation 4 on October 21st.