in-migration vs immigration

in-migration and immigration both are nouns.

Word	Noun	Adjective	Verb	Adverb
in-migration	Yes	No	No	No
immigration	Yes	No	No	No

As nouns, in-migration and immigration are synonyms defined as:

in-migration and immigration: migration into a place (especially migration to a country of which you are not a native in order to settle there)

in-migration (noun)	immigration (noun)
migration into a place (especially migration to a country of which you are not a native in order to settle there)	migration into a place (especially migration to a country of which you are not a native in order to settle there)
	the body of immigrants arriving during a specified interval