Cold Fusion?

Cold fusion does not occur.

It is an example of what has been called by the Nobel laureate Langmuir "pathological science". In this case it might also be called wishful thinking.

Hence muons have no role in it at all. Science fiction, however, may.

By definition, Cold fusion is a nuclear fusion reaction that takes place at or near room temperature and normal pressure instead of the millions of degrees required for plasma fusion reactions.