There is vast amounts of evidence for dark matter existing.
Dark energy is an unrelated concept with a similar name, and there is not really evidence for it; it is speculated because the equations of general relativity imply the need for an additional term to justify the inflation of the universe, but it's not at all clear what this term corresponds to in terms of matter.
No there isn't. There's a bunch of evidence that the current model used for cosmological dynamics (Friedmann's equations) don't work unless there's a lot of undetected stuff called dark matter.
Until someone rules out stuff like using the full nonlinear Einstein equations vs Friedmann equations, or that the presumption of homogeneity/isotropy is wrong, (there's more stuff here that hasn't quite been excluded by observation) then the best we can say is that "We need some extra matter called dark matter for the standard cosmological model to work"
Dark energy is an unrelated concept with a similar name, and there is not really evidence for it; it is speculated because the equations of general relativity imply the need for an additional term to justify the inflation of the universe, but it's not at all clear what this term corresponds to in terms of matter.