Westmarch is a town and social hub in Diablo Immortal. Currently, it is the only town we are aware of, though others may exist.
"Explore the sprawling streets of Westmarch in a time before Malthael’s corruption. The city is always bustling with activity as visitors from all over the world come to marvel at its sights, enjoy its landmarks, and more.Westmarch is where you can meet all your adventuring needs. You’ll have access to your stash and vendors, but more importantly it’s the place to meet fellow travelers, relax and take a breather."