What does it mean?
Life is not easy. Sometimes you just have to play the cards that you are dealt.
Life is being compared to a game of poker. In the game you get several cards. Whether you win or lose depends on how well you play those cards.
Life gives you some advantages/disadvantages. You may be rich or poor. You may be handsome or ugly. You may have a good heart or a bad heart (both emotionally and physically). You may have intelligence or be a slow learner. You may be strong and healthy or weak and sickly. These are the cards that life deals to a person. What they make of these "cards" depends on the person who gets them.