Why am I only now finding out about this card?
It has just come to my attention that Clayton's nonprofit foundation, Kershaw's Challenge, has their own exclusive Topps Baseball card.
From what I understand, this card was never inserted into packs for collectors to find. Instead, they were only available directly from the pitcher himself. All a fan had to do was to personally write to him. Check out pics of it above and below.
As you can see, it uses the exact same image and card design from Topps' 2016 flagship Baseball card set, but includes something different on the reverse.