Since it was released for Steam Early Access two months ago, H1Z1 has become a huge hit for Daybreak Game Company (former Sony Online Entertainment). Now they have announced on Twitter that they've reached one million sold games one Steam, and it still hasn't been launched on consoles and it's still very much in Early Access.
H1Z1 was previously only announced for Playstation 4, but when Sony sold the studio, they also said they were going to make a version for Xbox One. That means there's still a huge untapped market waiting for the game that has the potential of becoming a major multi-million seller.