https://www.pcgamer.com/a-future-rainbow-six-siege-update-will-nerf-lion-buff-lmgs/

A new batch of nerfs and buffs announced as part of Ubisoft’s new Designer Notes series could see a significant shift in the Rainbow Six Siege meta. The most notable is a hard nerf for Lion, who has seen a near-100 percent pick rate throughout the Pro League since his release. Other important changes include a mix-up with Hibana’s kit, Vigil’s gadget, and a universal damage buff for light machine guns.

The post puts forth a few graphs to give players some insight into how Ubisoft makes balancing decisions. The graphs map all the operators based on their pick rate and win rate to find anomalies that need correcting. On one end of the spectrum you have Tachanka, who has the lowest pick rate of any operator as well as the lowest win rate. No surprise there. On the other end sits an operator like Lion, who has an extremely high pick rate and win rate, and Ubisoft wants to do something about that.