respond vs come back

respond and come back both are verbs.

Word	Noun	Adjective	Verb	Adverb
respond	No	No	Yes	No
come back	No	No	Yes	No

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

Other hyponyms of respond include call back, counter, field, sass, rejoin, repay, retort, return, riposte, bridle.

respond (verb)	come back (verb)
show a response or a reaction to something	be restored
respond favorably or as hoped	go back to something earlier
react verbally	answer back
	even the score, in sports