The United States used Pakistani soil for its military and drone operation for many years. Getting allowance from former President General Pervez Musharraf through US-Pakistan Drone Deal helped the US to set their drone bases in Pakistan, but they were still bound to strike only that target given by Musharraf administration.
After General Musharraf’s departure, Zardari administration showed flexibility in the drone deal which allowed the US to carry out drone strikes without Pakistani government’s approval. Hence during 5 years of Zardari government, highest number of US Drone strikes were carried out.
During Nawaz Sharif’s tenure, Pakistan witnessed fewer drone strikes as compared to Zardari government, but the United States still had its influence in Pakistan which allows them to carry drone strikes.
Since Imran Khan assumed the office as Prime Minister, not a single drone strike was carried out by the US on Pakistani soil. According to Airwars head Chris Wood, who monitored US drone strikes, Imran Khan has always been against the US military or drone bases in Pakistan, that’s the reason why no US drone strike was carried out on Pakistani soil since he became the Prime Minister of Pakistan.