The Guardians of the Galaxy creative team gets to do a spin-off with a very similar name. Like the GotG series, this book is not 616 canon–it presents characters in an alternate future timeline.
It does, however, link directly to the GotG timeline. Martinex quits the team for a bit to join up with future versions of Ghost Rider, Vision, Firelord, Phoenix, and others.
Nonessential–for fans of the main book or completists (like me) only.