People tend to hang out with like-people. They spend their time and energy on relationships with people who have the same interests as themselves, maybe it is political belief, art or culture; for others it is their experience as a minority that brings them together.
Regardless, people form communities and find their home with people that share things in common.
For migrants, often our social cliques revolve around our first culture. It’s just easier you know? We eat the same foods, speak the same language and listen to the same music. Our communities become a refuge from the surrounding culture and maintain that little bit of home which is missing from our lives.