TTP was formed by several small groups operating in the tribal areas of Pakistan and to a lesser extent in the North-West Frontier Province (NWFP), and has always been almost entirely Pashtun in composition. The repression carried out by the Pakistani army has been ruthless, and the TTP has developed a record of extreme violence, including against civilians who are only remotely associated with the Pakistani state.
Signs of a TTP resurgence were already emerging in 2020, when it carried out over 120 attacks, but in recent weeks the group was able to launch its long-trailed ‘offensive’ in Waziristan. In July alone, the TTP carried out 26 attacks. + much more info here https://rusi.org/explore-our-research/publications/commentary/resurgence-tehrik-i-taliban-pakistan
TTP’s new leadership may have realized that the border dispute between Pakistan and Afghanistan remains an issue that resonates with Pashtuns on both sides of the Durand Line, including the Afghan Taliban. It is important to note here that the Afghan Taliban has refused to recognize the Durand Line as a settled border between Afghanistan and Pakistan despite pressure from Islamabad.
https://thediplomat.com/2021/08/the-ttp-has-redefined-its-goals-should-pakistan-be-worried/
Attempted enforcement has reportedly led to clashes (some fatal) between the Taliban and TTP over operational restrictions placed on the latter.
77. Despite growing distrust, TTP and the Taliban carry on with relations mainly as before. A reunification took place in Afghanistan between TTP and certain splinter groups in the period from December 2019 to August 2020. This included the Shehryar Mehsud group, Jamaat-ul-Ahrar (JuA) (QDe.152), Hizb-ul-Ahrar, the Amjad Farooqi group and the Usman Saifullah group (formerly known as Lashkar-e Jhangvi). AlQaida was reportedly involved in the moderation between the groups.
78. The return of splinter groups to the TTP fold has increased its strength, of which current Member State estimates range between 2,500 and 6,000 armed fighters, with one Member State assessing that the upper range is more accurate. The group has been led since June 2018 by Noor Wali Mehsud (QDi.427). 33 The deputy to Mehsud is Qari Amjad (not listed). The group has distinctive anti-Pakistan objectives but also supports the Afghan Taliban militarily inside Afghanistan against Afghan Forces. The group is traditionally located in the eastern districts of Nangarhar Province, near the border with Pakistan.
The question is how much control Pakistan and ISI can have over the development in Afghanistan. It is likely that ISI will be unable to prevent groups infiltrating not only in the former https://en.wikipedia.org/wiki/Federally_Administered_Tribal_Areas that since 2018 is merged with https://en.wikipedia.org/wiki/Khyber_Pakhtunkhwa but in other regions as well.
Pakistan on Friday said it would ask the incoming government in Afghanistan to act against the banned Tehreek-i-Taliban Pakistan (TTP).
https://www.dawn.com/news/1641737