If you claimed the Earned Income Tax Credit or the Additional Child Tax Credit, there is a new law that requires the IRS to hold these types of refunds until Feb 15.
According to "Where's My Refund" webpage, "*The IRS has begun to release taxpayer refunds for those claiming the Earned Income Tax Credit and Additional Child Tax Credit. However, these refunds likely won’t start to arrive in bank accounts or on debit cards until the week of February 27."