They basically structured the deal as buying stock in the company and investing $400M.
Letting them focus on their core business while still having a large financial stake in AI cars.
The big development is that self driving cars turned out to be an extremely hard problem which didn’t match company timelines (or potentially company business models, if for example AI kits can get installed in existing cars and brands for which they become the denominate call network) and they outsourced it to one of the best companies around.