“Alien” refers to people who are not citizens of the country in which they live. This means that they cannot have the same privileges as a citizen.
“Alien” carries stronger connotations as well. It suggests someone who cannot be assimilated, someone fundamentally different from “us”, and thereby threatening. When used to criticise someone or something, e.g. “this is alien to our way of life”, it seeks to force those who identify with the “us” to distance themselves from the people described as “alien”.
10 March 2002