The difference is that ISIS/ISIL has the support of the Sunnis due to Maliki & Shia policies treating Sunnis as 2nd class citizens. Hence they have taken over the Sunni areas.
Remember in the past these Sunni tribes defeated alqaeda & ISIS in the past & have now joined them as a last resort.
TTP will never receive such support from the masses of Pakistan, plus our armed forces don't suffer from divisions etc.
There will be isolated incidents but no chance will they take over.
Two completly different countries. These arabs countries take secterian hatered to another level, which we havent seen in Pakistan yet. I don't know what the **** Iraqi president expected, it was only matter of time before extremist sunni from all over the world joined ISIS.