According to TMZ Sports, the WWE cited its decision to not punish Lesnar—and allow him to face Randy Orton for their scheduled SummerSlam match on August 21—because Lesnar is a part-time performer. The league only holds full-time performers to its wellness program that prohibits PED usage.
Although the UFC cross-promoted WWE for UFC 200's main event card of Lesnar vs. Hunt, the WWE's final decision to not punish Lesnar is out of the jurisdiction of the UFC. Along with being a former UFC heavyweight title holder, Lesnar has competed in the WWE dating back to the early 2000s. Lesnar is currently under contract with WWE but has only been in 19 WWE matches between 2014 through 2016 (four, eight, and seven matches in those respective years). According to wrestling experts, the average contracted full-time WWE wrestler performs in more than 200 matches annually.
So for now, Lesnar will get to keep his $2.5 million purse from UFC 200 and make more money at SummerSlam in late August. This may not sit well with Hunt, giving him more room to gripe about Lesnar's victory and for the UFC deciding it will not fine Lesnar for his failed drug tests.