You can trigger a Microsoft Flow from Dynamics 365 Command Bar and create various posts, like messages in Microsoft Teams. Great! It would be really convenient if we could also replicate these messages as native Activity Feeds Posts inside Dynamics 365 database, thus directly visible on the entity form. Unfortunately the Flow connector for Dynamics 365 Customer Engagement doesn't expose the Regarding field when trying to define field values in the "Create a new record" step.

Please expose the Regarding field for Microsoft Flow. Since Activity Feeds are still very much present in V9 Unified Interface, it doesn't look like there's a plan to deprecate them, so fully supporting them as a mechanism for status updates related to business records would be very welcome.