Conventional traditional Jewish teaching is that Ishmael repented of the evil in his life and permanently changed, while Esau repented for a time but returned to his evil ways.
Traditional accepted Christian understanding is that Esau needed repentance and struggled with it.
There are innumerable Jewish explanations of this:
http://www.torah.org/learning/ravfrand/5770/vayishlach.html
...Eisav did Teshuva but then apparently went back to his old ways. His Teshuva did not last. This is contrasted with Yishmael, who repented and the Teshuva did last until the end of his life...
https://www.meaningfullife.com/social/toldot-the-plot-thickens-jacob-esau-two-nations/