A 5v5 PvP conversion of Arma 3 developed by Bohemia's indie team. Free to play as of right now (prototype).
https://www.projectargo.net/
https://store.bistudio.com/products/project-argo
https://youtu.be/l1HCv5VLO_c?t=2m52s
Bear in mind, dedi on linux is not supported.