human beings vs homo

human beings and homo both are nouns.

Word	Noun	Adjective	Verb	Adverb
human beings	Yes	No	No	No
homo	Yes	No	No	No

As nouns, homo is a hypernym of human beings; that is, homo is a word with a broader meaning than human beings:

human beings: all of the living human inhabitants of the earth
homo: any living or extinct member of the family Hominidae characterized by superior intelligence, articulate speech, and erect carriage

Other hypernyms of human beings include group, grouping, human, human being, man.

human beings (noun)	homo (noun)
all of the living human inhabitants of the earth	any living or extinct member of the family Hominidae characterized by superior intelligence, articulate speech, and erect carriage
	someone who is sexually attracted to persons of the same sex