They'll simply copy Google's playbook. First, clearly highlighted as advertisement results, usually the first three, so just with muscle memory you'll scroll down right away. Then they get bigger. Then the highlighting gets removed. Then it's just a tiny badge saying "advertisement".
This is something that I noticed after doing a Google search on a new machine without uBlock Origin installed. I was unable to identify that the first link was an advertisement to a competitor's product of the brand I looked up. I remember adverts used to be highlighted really well in Google searches earlier.
If I am unable to differentiate between an ad and a search result then neither can a lot of non technical users including my parents.
Can't wait to see ChatGPT ads