Views contextual filters taxonomy name 2 fields using same vocabulary
If I understand your question correctly, out of the box the easiest way is to add a Contextual Filter Content: Has Taxonomy Term Id. This one does not care whether you have 1 field or 20 that reference taxonomy terms.  Further details within are whether you want to match from URL on term id or term name, etc.

I came across your question whilst seeking an answer to mine How to filter on taxonomy term but only match one field on the node, where two fields (primary and secondary) both use the same vocabulary which I think is different.