[Brightcolours]

Conceptually mirrorless cameras are vastly superior to DSLRs when it comes to tracking.
A DSLR is essentially blind - it simply doesn't know what it is tracking. It can detect phase changes in the AF module covering an object.
A mirrorless AF _COULD_ interpret the image. Thus it _COULD_ know the thing that it is tracking.
Whether it actually CAN do that today depends on the specific camera. Of course, the latest and greatest are better than older models here.
Given Canon's history with sports/wildlife photography, they should be good.
Whether they are better than Sony - who had more experience with eye-tracking than all others - is a different question.
It does also depend on the specific setup.

https://www.youtube.com/watch?v=GyBZ2aFk93I

The newest DSLRs, like the Nikon D4/5, D850, D500, 5D mk IV, 1D-X II/III, 90D have exposure sensors that act like low resolution image sensors, giving the possibility to actually identify and track subjects in a similar manner (with more or less performance depending on the make/model).
That is why cameras like the D850 and 1D-X mk III have shown such progress in subject tracking, even against difficult backgrounds or even disappearing for moments behind foliage for instance.