This was reported in the official twitter Guerrilla Games.
Munnick has worked at Guerrilla since 2011 and was the lead producer for Horizon. The developer was 44 years old, the cause of death is currently unknown.
With shock and sadness, we inform you that our lead producer Patrick Munnick is no longer with us. We will forever be grateful that our beloved Patrick, who was so dear to the whole team, worked here.
Head of the studio Hermann Khulst also brought his condolences.
My heart is breaking for Patrick’s wife and children. Our entire team will miss his presence, his wonderful sense of humor, and most importantly, his friendship.