Khalil Mack
Mack was one of the best pass rushers in the league and won the Defensive Player of the Year award in 2016. The Raiders didn’t expect him to go anywhere but he cost them a lot of money. That’s why they reluctantly traded him to Chicago in 2018. The Bears rejoiced and made him the highest-paid defensive player ever (via Sporting News).

The All-Pro star played well in Chicago and helped them to the playoffs. But he also suffered from injuries during his time in “The Windy City”. In the end, he left them with a difficult choice because he took up a lot of cap space. They traded him to the Chargers because it was good business. The Bears narrowly won the trade with the Raiders but gave up a lot.