Shenzhen is 3 hours ahead of Islamabad
Best overlap: 8:00 AM to 3:00 PM in Islamabad is 11:00 AM to 6:00 PM in Shenzhen.
For the smoothest call, aim inside 8:00 AM to 3:00 PM in Islamabad, i.e. 11:00 AM to 6:00 PM in Shenzhen. That's a roomy 7 hours of common time each day, so finding a slot that suits everyone is rarely a problem.