When attempting to add the Subject field — a standard field on the Event object — directly to a Data Table component in a Screen Flow, the field doesn't appear in the list of available columns. However, other standard Event fields, such as Start Date/Time and End Date/Time, are available for selection.
You can manually hardcode the standard 'Subject' field name in the Data Table column configuration using the exact API name: Subject
After adding the column by typing Subject directly, The Subject values display correctly in the Data Table at runtime.
https://developer.salesforce.com/docs/atlas.en-us.object_reference.meta/object_reference/sforce_api_objects_event.htm
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