PCB can't do much, which is sad reality, shouldn't do much and I have to say most of the blame goes to PCB itself. No, I am talking about the March '09 incident (that was the root cause, but it's more than 10 years since), rather PCB themselves went through the compromised route when they allowed International players to opt out of PSL games in PAK.
PCB can't get it both ways - allow players in PSL without committing to come to PAK (So, that PSL brand/broadcasting value doesn't suffer), and then react at International boards/players' unwillingness to visit/tour PAK.
PCB has to solve it the tough way - first make sure that every player that participates in PSL (even Steve Smith), MUST unconditionally agree to play in PAK, obviously, subject to security situation. If it's with "phattichar" players, so it be - a phattichar PSL is better than a phattichar touring team making the mockery of a cricket series.
Second - the tougher job, make sure that the PSL is held entirely in PAK and without much incidences, unless there is a nuclear war. Couple bombs blasting here an there isn't a big deal these days anywhere, but PCB's security system must have to be functional enough not to allow few goons target practicing at the International team bus in the heart of PAK's top Metro City.
Third, and this is where I would expect WK & E Mani to deliver better than previous ******* - don't blame any board and don't accuse any one else for this situation. That'll only isolate PAK more, SLCB has been a fantastic supporter for PCB, PAK cricket and they maintain a healthy relation with every cricket board despite their internal politics - which allowed SRL to host every team in 90s & 2000s, despite suffering one of the fiercest, deadly civil war.
Fourth - every International series has a purpose. Host SRL (whichever squad they send) with proper dignity, arrange sufficient security measures and play the games with proper spirit. You only can play against whom are there and those players who have agreed to come deserve respect, should be treated like that. This is first proper series in PAK after more than a decade and a little progress towards the ultimate goal.