Updating source data for pivot table
Right-click on your pivot table, select Pivot Table options, and go to the Data tab.Under "Retain items deleted from the data source" you'll likely see "Automatic" selected.
You can also refresh data from a source table in the same or a different workbook.
The only way I can get it to update is by checking the ‘Hide items with no data’ in the slicer properties. I can’t believe the slicer will not update after a data model refresh!