Microsoft has their shit locked down tight when it comes to Xbox One exclusives. Respawn Entertainment's Titanfall, which is like Call of Duty but with armored mech suits, is the big one here.
But while Titanfall won't be a launch title, there are plenty more Xbox One exclusives releasing earlier. Just check out Dead Rising 3, Forza 5, Ryse, Quantum Break, Killer Instinct, Sunset Overdrive, D4, and plenty more as evidence of that. PS4 has some as well, but XB1 comes out on top here.