Best answer by Ahmad
Well simply the iPhone is MUCH more popular device and sells much better than any Android on Koodo. Koodo can't carry every android in the market, there are just too many so they have to pick and choose. While it'd be nice for them to carry the Note 5, they do carry the Note 4.
Also, at this point don't expect them to carry the Note 5 until at least the Note 6 comes out. Koodo will not comment on any possible releases until officially announced on their website/fb page.