Pakistan and Afghanistan are two neighboring states sharing both religious and cultural identities as well as multiple crossing points along their borders. Both countries have had ups and downs in their bilateral relations, however, the takeover of the Taliban in Afghanistan, the nexus between Taliban and Tehreek-e-Taliban Pakistan (TTP) led to intensifying security situations in Pakistan which ultimately resulted in tightening bilateral relations between the two countries. This paper uses a secondary qualitative research design where data has been collected from already existing sources and analyzed with the help of the content analysis method. The nexus between the Taliban and TTP is a result of factors such as religion, common ethnicity, and ideological monolith. TTP allegedly used Afghanistan soil to engage in terrorist activities against Pakistan which brought mistrust and uncertainty in bilateral relations between them.