Pro Advanced autofocus
D5 has 153 AF points of which you can select 55. 99 AF points are cross-type (of which 35 are selectable). 15 AF points work with f/8 lenses (of which 9 are selectable). The autofocus works down to LV -4.
Autofocus is amazingly fast at 14 frames per second with top of the class accuracy (in tests performed by Tony Northrup it was only second to 1DX Mark II in terms of how many shots were in focus having just 6% fewer of shots be in focus).