Expressions used in Everyday Spoken English in Social and Professional contexts
In a game of cards, to 'stack the deck' means to cheat or to give yourself an advantage. If you say the cards are stacked against you it means that a situation holds a disadvantage for you from the outset. To have the card stacked in your favour however implies that the way things are arranged gives you an advantage over others. This is an idiom used in both professional and social contexts.