Collection Eligibility Confirmed Achievement in Halo: The Master Chief Collection

This achievement can be earned on the Easy difficulty (or higher) on Pillar of Autumn.

During the very last cutscene in Pillar of Autumn, where the camera is set inside the titular ship's hanger and you can see Keyes' Pelican docking, pull/hold your right thumbstick to the right. This will pan the camera slightly, revealing a cryo-pod with Master Chief and in turn unlock the achievement.