JI in Pakistan most commonly stands for Jamaat-e-Islami Pakistan.
Jamaat-e-Islami Pakistan (جماعت اسلامی پاکستان) is a major Islamist political party in Pakistan. The name translates to "Islamic Party of Pakistan" or "Islamic Assembly of Pakistan". The party advocates for the implementation of Islamic law in Pakistan and is known for its social and political activism.
Therefore, when you see the abbreviation "JI" in the context of Pakistani politics, it is highly likely referring to Jamaat-e-Islami Pakistan.