This just seems like a lot of fanfare for something not that exciting (for those that keep up with other movers in the space). It's announcing Tesla's Navigate on Autopilot (from October 2018) is now available for GM cars (in 2021). The only difference (or improvement if you see it that way) is how they check for driver attentiveness. Instead of Tesla checking for torque applied to the steering wheel, GM is checking for eye-gaze.
Ultra Cruise (Oct 2021) is basically a mix of regular Autopilot features (and FSD beta if we're including non-production features that some customers can get) from even more years ago Tesla, but limited to less roads than Tesla's regular/old Autopilot.