From Halopedia, the Halo wiki
Team Player was a career award found on the web version of Halo Waypoint from 2009-2014 and on the Xbox 360 version until its discontinuation in 2022. It was represented by a pair of M6 Magnums on a triangular medal with a red, white and blue ribbon. The award consisted of 14 achievements related to cooperative play. These achievements were organized into four tiers.