Yes, I know they are close allies-now.
Ofcourse, their primary foe is India.
They have been close allies for close to 50 years & that alliance is undergoing a transformation.In addition to joint production of several weapon systems(tanks,missiles,aircraft),the Pakistanis are looking at building a corridor from the new port of Gwadar through Pakistan’s northern areas upto China.Very secure means to deliver Iranian gas to the PRC.