Yes, You can Access Your On-Premises Applications Directly in Teams.
To access your on-premises applications in your channel through pinned tabs. This can include your SharePoint sites or other business applications.
This flow is made possible using the Azure Active Directory Application Proxy. Many customers currently use Application Proxy to provide single sign-on (SSO) and secure remote access for web applications hosted on-premises. These flows don’t use a DMZ or VPN – all traffic goes through a light-weight agent on-premises that only uses outbound connections. You can learn more about the Application Proxy flow in our documentation.
Reference Document-https://techcommunity.microsoft.com/t5/microsoft-teams-blog/access-your-on-premises-applications-directly-in-teams/ba-p/65245
Thanks,
Sayali
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