Arma 3's first paid-for, third-party DLC will be out tomorrow, and it will offer a 10-mission singleplayer campaign, 17 multiplayer scenarios and more than 40 new vehicles and vehicle variants across its 1980s Cold War Germany map.
The DLC, called Global Mobilization - Cold War Germany, features 419 square kilometers of terrain in both sunny summer and snowy winter variants, making it the largest Arma terrain to date. As well as the campaign, multiplayer scenarios and usual Arma 3 sandbox gameplay, the DLC will introduce 42 new vehicles and vehicle variants, 21 new weapons including variants, and new character assets.
The campaign focuses on the battle over the inner German border from two perspectives: a private in the West German army and the leader of a tank platoon. The 17 multiplayer scenarios comprise 13 co-op scenarios and four competitive game modes, including a deathmatch called "Fashion Police", in which teams "can quickly change based on the clothing you wear".
As well as West and East German armies, the DLC features troops from Denmark, who will provide a "smaller but viable military faction".
Bohemia insists that third-party DLC, announced last year, is not simply "paid mods". In an FAQ it says: "We believe that these DLC packs would not have otherwise existed or be possible as mods of similar quality and scope". Third-party DLC "will never replace something that was available for free", it says.
I'd say it at least has a leg to stand on here—all third-party DLC must be a new project pitched to and approved by Bohemia, which provides "continuous feedback, assists with the Quality Assurance (testing) process, and offers legal, mastering, publishing, and promotional support" throughout development.
The two-person team behind Global Mobilization are called Vertexmacht. One of the developers is an animation lead at Bohemia Interactive Simulations, a separate entity to Bohemia Interactive, which is why this still counts as third-party DLC. You can read an interview with both developers here.
Bohemia haven't yet announced a price for the DLC. The Steam page is here, while the Bohemia Store page is here.