The Iranian government has made a ruling that Pokemon Go will be banned in its country. Iran's High Council Of Virtual Spaces cited security concerns about how much data Niantic can access about players through the game's servers. Other sources, including the BBC, have indicated that the ban came as a result of failed negotiations between Iran and Niantic about new terms for the game's presence.
Another likely reason for the ban is due to the game's content butting heads with the Islamic State's religious regime.
Back in 2001 the Pokémon card game had been been banned via a fatwa (religious ruling) by Iran's General Secretariat of the Council of Senior Religious Scholars. The reasoning was that it contained "forbidden images", like crosses and a six-pointed star, thought to be propaganda for Christianity and Judaism respectively. The council also considered the popular card game to be a form of gambling, which is illegal in Iran.