By default Microsoft pinned the Chat Icon that opens Teams for personal use. Why you would want to have this enabled in an enterprise environment I’m not sure of. So here is a quick guide in how to remove this using Intune Settings Catalog.
Begin by navigating to Devices then select Configuration profiles
Select Windows 10 and later as your Platform and Settings catalog as Profile type
Give your profile a name
In the the settings picker you can either search or navigate to the Experience category. Select it, then tick the box next to Configure Chat Icon
Change the setting from Windows default to Disabled.
Assign and save your profile
That’s it, now just sit back and watch the Chat icon disappear