On windows 10 machine, I was browsing some recipe cook books on chrome incognito mode. I was searching on youtube and google.
I get on my phone(android) and browse my regular news/sports websites and I see the ad for the exact cookbook I was searching for on my pc. I’m not logged in to any account, so the only way to get my cookies/history is through ISP. Again, separate device, not connected to any account, just under same wi-FI network.