On 7 May 2024, officials from Russia and the partially recognized state of Abkhazia signed an income tax treaty. The treaty is the first of its kind between the two jurisdictions and will enter into force after the ratification instruments are exchanged.
Note that Abkhazia is a contested territory that is recognized as an independent state by Nauru, Nicaragua, Russia, Syria, and Venezuela. Essentially all other countries recognize Abkhazia as a sovereign territory of Georgia.