You pick up the phone and call them ...
A city-dweller is an "urbanite."
citizen
An urbanite is someone who lives in a city. A native is someone who was born and reared in a particular place.
Someone who lives in Haiti is called a Haitian.
tangerina
They are Swiss.
Mexican
Pakistani
A person who lives in Lubbock is called a Lubbockite.
They are called Tampons.
You can call them a fellow resident or a neighbor.
Well, some would call such a person a Hermit.