Superman & Batman Generations 2, book 4
John Byrne2001

2008 : A foe thought long dead returns - in a powerful mechanical body - and only the combined strength of Green Lantern, Knightwing, Cyborg, and brand-new Flash have any hope of stopping him. Plus the inheritor of an incredible heroic legacy makes a fateful decision.

2019 : Superman returns to Earth to share an incredible discovery with Batman, as the Darknight Detective learns of the startling role a juvenile Superboy played in Bruce Wayne's life. Was the death of the Wayne part of a larger, unguessed-at plot?