DC Comics has revealed the first bits of information on Action Comics #1000. Scheduled to arrive in 2018, the anniversary milestone is framed as a major event by DC Co-Publisher Dan Didio in the "DC Meet the Co-Publishers" panel at New York Comic Con.
"It's Superman's 80th birthday in the same year that Action Comics #1000 comes out, and we're leaning into that in a big way," said DiDio.
At its current twice-monthly shipping schedule, Action Comics #1000 would arrive in late March, 2018. Superman was "born" (i.e. debuted) in May 1938, making May 2018 his 80th birthday month.