Why can't Mexicans play Uno?
Because they can't get a green card.
Why can't Mexicans play Uno?
Because they can't get a green card.
This is a dark joke that plays on the stereotype of Mexicans and immigration issues. The punchline uses the 'green card' term, which is both a card in Uno game and an immigration document. It suggests that Mexicans cannot play Uno because they are not legal immigrants which is offensive and untrue.