Off the top of my head:
4K
F-Log (via HDMI, also 4:2:2 via HDMI)
Headphone jack (in grip)
3.5mm mic jack
AF-C profiles
Bigger/Better EFV
Zebra
Peaking during video recording
Live audio monitoring that can be adjusted by assigned buttons
More AF points and more contrast detect AF points
Tilty sceen
Both slots are UHS-II type (only slot one is on the xpro 2)
Battery grip (xpro2 obviously doesn't have
11fps in boost mode and apparently it can go 14fps with some restrictions
I think the buffer is bigger