The Minkowski sum and the sumset have basically the same definition: $$A+B=\{a+b; a\in A, b\in B\}.$$ As far as I can tell, the first name is more often used when we're dealing with vectors (i.e., in vector spaces, linear normed spaces, topological vector spaces, perhaps topological groups, too), the other one is more frequent in number theory and additive combinatorics. (But the distinction might not always be clear.)
The tag sumset exists at least since December 2013. I have collected some related stats in the tagging chatroom. At the moment, there are 94 questions tagged sumset.
The tag minkowski-sums was created in May 2023. At the moment, this tag contains 8 questions.
Since the tag sumset exists for ten years, it is not very surprising that it is used in both meanings. Among the questions with this tag, there are 20 questions tagged real-analysis, 7 questions tagged general-topology, 6 questions tagged compactness
Question: Should these two tag be synonyms? Or would it be better to have two separate tags? If these two tags are kept as two distinct tags, what criteria should be use to choose the appropriate tag of the two?
(I will add that if the community decides that the tag minkowski-sums should be kept as a standalone tag, some questions that are now tagged sumset might need retagging.)
I am aware that there exists a big thread for discussing various tag synonyms - but since it is probable that the discussion here might include several options, a separate question seemed more suitable to me.