You cannot use a slicer directly as a chart axis in Excel. This is because Slicers are designed to filter data in pivot tables or pivot charts, but not as axis labels.

So, an alternative can be to:

a) create a pivot table, b) insert a pivot chart based on this pivot table, c) add a slicer connected to the pivot table.

The slicer won't become an axis, but it will filter the data.

Hope this helps.