Of course it has slight differences among a few regions. Aegean people has their own accents, Blacksea too. Eastern part of Turkey has also a different accent, but you can hear these slight differences only in rural areas. You can't hear it among educated people. Eastern parrt is an exception, you can hear a different accent even in city centres.

"Does the Turkish language include accents or does it have one tone?" If you mean, "does Turkish have tones like Chinese?" then definitely not. :D It's not a monotone language either. There are certain accents in words and conjugated verbs, as well as an overall intonation of sentences, in Turkish.