They are not related at all. Dark matter is visible on the scale of galaxies, dark energy on the scale of the universe. Dark matter is currently the best model

They are not related at all. Dark matter is visible on the scale of galaxies, dark energy on the scale of the universe. Dark matter is currently the best model that can describe the rotational curves of galaxies under the assumption that general relativity is correct. Since GR has so far stood all tests extremely well, this is a very compelling argument for the existence of dark matter. There are also some more direct observations, such as gravitational lensing caused by dark matter.