Remember when Quads replaced Trios, everyone had a wobble, Activision claimed to have two game modes would dilute the player base, then promptly restored it? Well, it seems that logic has gone out of the window because now you can add Duos to the list.
This is a very much welcome addition, though. The new model is the same as Trios and Quads, although the dynamic naturally shifts with teams of two. You'll need to defend yourself and your teammate more closely, as you'll have less support available.
Duos is quite possibly the ultimate test of friendship and teamwork; with only one other teammate to rely on, you’ll have to coordinate your strategies, make good callouts, and most importantly, hit your shots if your fellow Operator’s life is at stake.
You'll also need to consider consolidating roles into one operator with only two available, using the Overkill perk.
Activision recommends and Assult rifle-sniper build for success, but also suggest you keep a few close-range weapons and a fast car on standby.