Rockstar keeps their release dates pretty close to the chest, and fairly far out of reach.
Though based on the record of Danish retailer Coolshop, who did give us the right GTA V date, we may have a firm idea of when Red Dead Redemption 2 will be out. Based on the site, the prequel (which in reality is the third game in the Red Dead series since Red Dead Revolver is a thing), will drop on June 8.
Red Dead Redemption 2 is currently slated for a second quarter release on PS4 and Xbox One. This time it'll focus on an outlaw named Arthur Morgan, and Sony has a timed exclusivity agreement for "some" online content on PS4. That's basically all we know at the moment!