From Command and Conquer Wiki

Phoenix Base was one of GDI's smaller bases in the twenty-first century, tasked with protecting and maintaining civilian settlements in the vicinity of the city of Phoenix. Led by commander Tao, it was a small base, enough to house permanently a Tiberium refinery and a contingent of soldiers. It was one of the bases overrun by the Brotherhood of Nod in the initial stages of the Second Tiberium War. Tao was executed personally by general Vega who led the assault.

Commander Michael McNeil was ordered to recapture the base with assistance from jump troopers. However, they didn't arrive soon enough to save Tao or the local civilian village.