[have|hold] (all|) the aces

to be in an advantageous position when competing against someone else

The phrase likely dates back to the 19th century when gambling was a popular pastime, and people frequently used card-related expressions in everyday language. Over time, the phrase "have the aces" has been adopted in broader contexts to describe any situation where someone holds a position of power or advantage.

The basketball team holds the aces with their great players, teamwork, and strong coach, so they are likely to win the game.
The negotiator held all the aces with their persuasive arguments, information, and bargaining power, and got a favorable deal.
The student had the aces going into the exam, but they didn't study enough and ended up doing poorly.
The team that has the best players, the best strategy, and the most resources has all the aces in the game.