AnyConnect does not include MFA, but you are not required to use Duo, you can pick any SAML vendor your want. Almost all our clients have integrated AnyConnect with Azure AD/Office 365 and just use the MFA included in Azure AD conditional access https://documentation.meraki.com/MX/Client_VPN/AnyConnect_on_the_MX_Appliance/AnyConnect_Azure_AD_SAML_Configuration
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