The Canon 80D replaces the old 70D of July 2013, mostly adding a new autofocus system and a flicker shoot-through system needed for shooting under modern LED and sports lighting.
45 zone AF system, all cross points.
7,560 pixel RGB + IR light meter, also used for face tracking and other tricks.
Frame rate is the same 7 FPS as the 70D, and resolution is essentially the same as well (24 MP looks the same as 20 MP) and takes the same battery.
NFC: NFCTM2 compatible
Worthwhile improvements over the 70D would be the improved dynamic range, 100% viewfinder and the headphone jack for monitoring sound during video.