For the first time in its history, the Xiaomi custom MIUI Android skin has implemented 2-factor authentication (or 2FA) for this OEM's software ecosystem. So far, it works to send notifications to all devices connected to a single applicable account in the event of unfamiliar logins. However, there is no SMS-based verification as yet.
https://www.notebookcheck.net/MIUI-introduces-2-factor-authentication-for-Xiaomi-user-accounts.430827.0.html