What is the most expensive athlete trading card?

What's the most valuable athlete trading card on the market today? Are we talking about a rare vintage card from the early days of sports collecting, or is there a modern superstar whose trading card has skyrocketed in price due to their popularity and performance? Is it a baseball card, a basketball card, or perhaps something from a different sport entirely? And what factors contribute to the high value of these cards, beyond just their rarity and the athlete's fame?