The Taliban and ISIS-K are both fundamentalist Islamist militant organisations that seek to impose a strict Islamic rule on Afghanistan but they have deep religious and political differences. While the Taliban are content to rule Afghanistan as a nation, ISIS has since its inception aimed to create a borderless Caliphate that would ultimately conquer the entire world.
ISIS-K accuses the Taliban of abandoning Jihad and the battlefield in favour of a negotiated peace settlement hammered out in "posh hotels" in Doha, Qatar.
The group considers Taliban militants "apostates", making their killing lawful under their interpretation of Islamic law.
The ISIS-K first emerged in late 2014 and then declined around 2018 as they were targeted by both the Taliban and the US forces. According to NATO intelligence, ISIS-K has a strength of under 2,000 fighters and it draws many of its fighters from the ranks of the Taliban or Pakistan's Tehreek-e-Taliban Pakistan (TTP). There are reports that before the Taliban's takeover, several major attacks between 2019 and 2021 involved collaboration between ISIS-K, the Taliban's Haqqani network and other terror groups based in Pakistan.