According to a leaked AMD document, the PS4 exclusive, Horizon Zero Dawn is indeed coming to PC and Team Red will be bundling it with its Ryzen 3000 processors. The game will be available for free to every buyer of a Ryzen 5 3600 and above CPU till the 31st of July in the EMEA region (Europe, Africa and the Middle East).
TIMING: Campaign begins June 10, 2020, at 9:00:00 AM Eastern Time (“ET”) and ends on June 30, 2020, at 11:59:59 PM ET, or when the supply of Coupon Codes is exhausted, whichever occurs first. Please consult the world clock for time zone conversion information. To receive a Coupon Code, the participant must purchase an Eligible AMD Product during the Campaign Period from a Participating Retailer. The Coupon Code must be redeemed no later than July 30, 2020, to obtain Application downloads after which the Coupon Code is void.
You can read the document here.