ISPs have perfect knowledge of your IP, so if they can get even basic traffic logs from _anything else_ can reconstruct your browsing history more accurately than any other third-party. Since you are probably visiting your ISP's site regularly to pay your bill, there are also a lot of possibilities for them to regularly associate third-party cookies with your login. They also have the highest-quality ambient location data (outside of explicit app permissions) to link with all of that.