come in vs fashion

come in is not a noun while fashion is a noun.

Word	Noun	Adjective	Verb	Adverb
come in	No	No	Yes	No
fashion	Yes	No	Yes	No

come in (noun)	fashion (noun)
	characteristic or habitual practice
	consumer goods (especially clothing) in the current mode
	how something is done or how it happens
	the latest and most admired style in clothes and cosmetics and behavior

come in (verb)	fashion (verb)
take a place in a competition; often followed by an ordinal	make out of components (often in an improvising manner)
to insert between other elements
be received
to come or go into
come into fashion; become fashionable