Studies and Observation Group (Earth-7162)

"Back in '64, the CIA gave up control of covert operations in Southeast Asia, handed it over to the US Military. From that, MACV-SOG was born."

- Frank Woods

The Military Assistance Command, Vietnam - Studies and Operation Group (also known as MACV-SOG or SOG) was a highly classified, multi-service United States special operations unit which conducted covert unconventional warfare operations during the Vietnam War.

Source

 * https://callofduty.fandom.com/wiki/Studies_and_Observation_Group