If there were evidence, then it would no longer be a theory, but a fact.
That's not really how it works. Theories don't graduate into facts.
Theories
explain facts. Theories, in a way, are made out of facts. That's why we have things like the germ
theory of disease, which explains the fact that diseases are caused by germs. Or the theory of gravity, which explains the fact that gravity attracts massive objects together.
Or the theory of evolution, one of the best-supported theories in all of science, which explains the fact that creatures evolve by random mutation and natural selection acting on the genetics of populations.
See?