It's primarily a skill game, although luck plays a huge role. In any single given hand, luck is the predominant factor in who will win or lose. However, poker players don't play a single hand. They play hand after hand after hand & and overall, skill dominates.

Poker is 100% a game of skill in the long run. However there is a large element of luck in the short term. Professional poker players mitigate the luck aspect by consistently making mathematically superior decisions and therefore winning in the long run.