Windows Hello for Business is considered two-factor authentication based on the observed authentication factors of: something you have, something you know, and something that's part of you. Windows Hello for Business incorporates two of these factors: something you have (the user's private key protected by the device's security module) and something you know (your PIN). With the proper hardware, you can enhance the user experience by introducing biometrics. By using biometrics, you can replace the something you know authentication factor with the something that is part of you factor, with the assurances that users can fall back to the something you know factor.