Emigrant
Immigrant, Migrant
noun
Someone who has to shift their dwelling is someone who moves their home (and in this case) to another country. They are an emigrant / immigrant. Welcome to this country, friend!
いじゅうしゃ
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
国外移住者になるのは容易なことではない。
It’s not easy to be an international immigrant.