come in vs pop in

come in and pop in both are verbs.

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

As verbs, pop in is a hyponym of come in; that is, pop in is a word with a more specific, narrower meaning than come in:

come in (verb)	pop in (verb)
take a place in a competition; often followed by an ordinal	enter briefly
to insert between other elements
be received
to come or go into
come into fashion; become fashionable