My iPhone is connected to a strangers?

My name is listed on my contacts as a man I have never heard of his calls show up on my recents and his search history shows up on mine. I don't share a phone plan or iCloud with anyone else I bought the phone new so it never belonged to anyone else. How did this happen and how do I stop it

Umm this is weird and alarming. You might be being watched so be careful. Go to iphone place

Change your iCloud password and sign out and sign back in. Also, I would recommend enabling two-factor authentication after doing that.