I don't know much about this stuff, but the first idea tha came up is something similar to what Bing/Microsoft does, where with each search there is an AI section using Google's Bard or whatever
It's in limited opt-in roll-out now. This is probably go gather some feedback (on quality, usefulness, and impact to advertising) before launching it more broadly and also because there isn't enough compute power (even for Google) to run a LLM job for the billions of searches that they delivery daily.
Some results are OK (saves a trip to wikipedia) but many long-tail queries produce terrible results (and it's really slow: it can take 5-10 seconds to render a result, long after I've scoped the top 3 links).
A great example of the sort of quality issue I had: if I search for [ <my name> string library c++ ] it says I'm the author of a popular string library (I am not). The result changes every few days, but is pretty persistent in showing me made-up results like that.
It's basically a summarization of Google search first page. The results lack depth.