poker vs card game

poker and card game both are nouns.

Word	Noun	Adjective	Verb	Adverb
poker	Yes	No	No	No
card game	Yes	No	No	No

As nouns, card game is a hypernym of poker; that is, card game is a word with a broader meaning than poker:

poker: any of various card games in which players bet that they hold the highest-ranking hand
card game: a game played with playing cards

Other hypernyms of poker include cards.

poker (noun)	card game (noun)
any of various card games in which players bet that they hold the highest-ranking hand	a game played with playing cards
fire iron consisting of a metal rod with a handle; used to stir a fire