If installed on any site collection other than the root site, it will be seen as an additional tab in the Teams channel.

1. Go to the tenant admin apps page from the below URL format and click on classic experience options.

   https://yourtenantname.sharepoint.com/sites/appcatalog/_layouts/15/tenantAppCatalog.aspx/manageApps
   
   
   



2. Click on Apps for SharePoint as shown below.

   



3. Select the Employee Directory application and click on Files and then Sync to Teams.

   These displays Sync to Teams successfully.

   



4. Navigate to Teams and click on Add a tab

   



5. Search and select the Employee Directory application. Then click on add.

   
   
   
   



6. Next, click on Save and you can see Employee Directory application in teams.