You can now use Amazon Cognito to let your users sign-in through identity providers that support Security Assertion Markup Language (SAML) such as Microsoft Active Directory Federation Services (ADFS). You now have an additional option with SAML for adding sign-in to your mobile and web apps in addition to Cognito user pools, social identity providers such as Facebook, Twitter, and Google, Open ID Connect providers, and your own authentication system. 

Source: Amazon Web Services News