Teams chat in Dynamics 365 Timeline
You have to Enable Team Chats in the activity list for the Timeline, just like you do for Email, Tasks, Phone Call, etc. Settings > Advanced Settings > Settings > Customization. Open the Entities section, find Cases, and expand that. Click on Forms. Choose the form you have set as your default. For us, we use the Case for Interactive experience, so click on the Name, it's a hyperlink. Once the form opens, double click on the Timeline box. That opens the Activities Tab Properties. Open the Activities tab. In the Filer By section, select Teams Chat. Click OK. Don't forget to Save, then Publish.