Your cookies are not shared between domains, meaning example.com cannot see cookies stored by otherexample.com, that would be a huge security risk for everyone and is something browsers have to keep secure.
Why is this is not possible you ask?
- Most platforms save your login cookies (used to automatically login when you visit facebook for example, so you don't have to repeat username/pass 24/7), so essentially if you would visit a malicious website that could see all your other cookies they would have access to all your stored saved logins.