In a seismic shift to the collegiate sports landscape, the two Southern California powerhouse universities — UCLA and USC — said Thursday they are leaving the Pac-12 Conference for the Big Ten Conference at the start of the 2024-25 season.In a seismic shift to the collegiate sports landscape, the two Southern California powerhouse universities — UCLA and USC — said Thursday they are leaving the Pac-12 Conference for the Big Ten Conference at the start of the 2024-25 season.