https://wccftech.com/horizon-zero-dawn-can-now-be-grabbed-for-free-on-the-ps-store/

As part of Sony's Play at Home initiative, Horizon Zero Dawn can now be added to your library for free via the PlayStation Store. Players will have until May 14th at 8 PM Pacific Time / May 15th at 4 AM BST / 5 AM CEST to do so before the promotion expires.

This is the Complete Edition of Horizon Zero Dawn, which means there's the Frozen Wilds expansion included. Both the base game and its only expansion were awarded a 9.5 score in our reviews from Chris Wray and Francesco De Meo.