American Express will refund $200 from your Business Platinum annual fee ($595) upon card renewal.
This is being sent out via email to some and it shows at the link above. Some are also seeing it as a banner ad in their online account.
It hasn’t yet gone out to everyone via email, but some with annual fees due much later in the year are already getting it, so I’d guess that it’s just being sent out in batches and ultimately everyone will get it (at least if your fee is due anytime in 2020). That’s my guess.
(Update: one reader was told this specifically by a rep that the appreciation bonus is for those whose annual fees renew between May 1 and December 31.)