It lines up with what I've experienced with the 1D X III, R5 and R6.
The very nature of how mirrorless focuses vs SLRs means that, until there is a significant breakthrough which likely won't be for a few generations, the autofocus of the very best SLRs will remain better for tracking subjects in complicated 3D situations with a lot of depth in the frame, assuming the body and lenses are calibrated together correctly, and the lens has an aperture big enough to take advantage of the SLR's many dual-cross-type focus points. The other end of this is that mirrorless is of course much more accurate when focusing on 2D scenes and don't require lenses and bodies to be calibrated together. Dual pixel focusing helps mirrorless a bit, but it's not enough of an increase in depth (not even a millimeter) to help if the camera has totally missed the subject to begin with.
Without going into the full breakdown, the quickest and simplest way I'd describe it (which I'm sure will make some of the more pedantic techbros here irate) is that SLRs 'see' in 3D while mirrorless 'sees' in 2D. The more complex depth—the 'more 3D'—you have in the frame the more the advantage goes to SLRs, and vice-versa.
It's going to be a long time before mirrorless becomes the more common design for professional sports and wildlife shooters. Sports and wildlife aren't the 2D subjects that mirrorless accels at. I'm loving mirrorless for portraits, any studio work really, and the occasional slower insect on my walks, but when it comes to hectic action crisscrossing all over the place, whether that's a person in a team sport or one animal in a herd, the Canon 1D X III and Nikon D500 and D6 are still my top picks.