The trailer for The Avengers just leaked and found it’s way online.
Check it bolow!

It seems the trailer is the after-credits scene of Captain America, the First Avenger.

The Avengers gets a worldwide release on May 4, 202
Starring Chris Evans (Steve Rogers), Robert Downey Jr. (Tony Stark), Chris Hemsworth (Thor Odinson), Jeremy Renner (Clint Barton), Mark Ruffalo (Bruce Banner), Scarlett Johansson (Natasha Romanoff), Clark Gregg (Agt. Phil Coulson), Cobie Smulders (Maria Hill), Samuel L. Jackson (Nick Fury), with Tom Hiddleston (Loki), and Stellan Skarsgard (Professor Erik Selvig).
Directing Joss Whedon,