After the reveal of Call of Duty: Advanced Warfare trailer, the pixel counters on Beyond3D forum have started to analyze the game. They estimate the game to run between 810p and 900p. So far they affirmed to get about 840p.
Digital Foundry have also made their research and they found about 884p but they admit that the number might be wrong.
Considering the Xbox One’s hardware limitations you should expect at 810p resolution of the game. This is the most appropriate resolution, but if some corners will be cutted and if Sledgehammer scales back some of the effects we can hope for 882p as well.
Source: Gaming Blend