X-Factor is the government-sanctioned mutant team led by Havok in X-Men '97 season 2.
With the X-Men scattered through time, Dr. Valerie Cooper fields X-Factor as an official U.S. response to the mutant crisis. Its roster includes Havok, Polaris, Multiple Man, Strong Guy, and Wolfsbane. Cooper uses the team to capture young runaway mutants seeking refuge with the X-Men, placing X-Factor in direct conflict with the more independent X-Force.
The name comes from Marvel Comics, where X-Factor has had several distinct incarnations. The 1990s version was also a government-backed mutant team, with Havok serving as its leader alongside Polaris and other familiar characters. That history makes X-Factor a more precise answer than X-Force, which is a separate team in the season formed around Cable, Jubilee, and Sunspot.