Well I suppose that the most important evidence in favour of evolutionism, assuming that there are still serious scientists who beleive in creationism, is the genetic \ fossil \ morphological comparison
All the species which are supposed to have a common origin based on the fossil and which have a similar look , have also similar DNA
Even more important
A few species which are nowadays morphologically very different but having a supposed common origin based on fossils , they have also similar DNA
The modification of DNA caused a substantial modification just of their external look
This is, in my opinion, a tremendous and probably a final evidence in favour of evolutionism