The crossover fans have been waiting for will finally take over cinemas in less than one year when the Guardians of the Galaxy and the Avengers take on their common enemy of Thanos in Avengers: Infnity War. It's an idea which has had all Marvel fans clamoring for a team-up since the Guardians were introduced in their first adventure in 2014, two years after the Avengers assembling for the first time in 2012.