Babar Azam, 22, is already establishing himself in the Pakistan side and is the favourite to replace Younis Khan at No. 4.
A right-hand batsman with free-flowing strokes, Babar made his name with three successive ODI hundreds against West Indies in the UAE and has played nine Tests so far. While he averages over 50 in ODIs and T20Is, Babar hasn't found the same form in Test cricket, where he averages 27.
There is little doubt about Babar's talent, though, and the stake-holders are willing to remain patient - rare in Pakistan cricket - as he evolves as a long-form batsman and finds his feet in Tests.
Usman Salahuddin, now 26, made his ODI debut as a 20-year old in 2011, following high-scoring domestic seasons. He was tipped as a promising prospect after Mohammad Yousuf's career ended abruptly, but scored only 5 and 8 in two innings in the West Indies before dropping off the radar.
Salahuddin once admitted that his international opportunity had come too soon - before he was ready - and that a couple of more domestic seasons would have prepared him better for the pressure. He's played six years on the domestic circuit since, and some league cricket in England, and now averages 47 after 92 first-class matches.
Salahuddin has 19 hundreds and 32 half-centuries, and in the most recent Quaid-e-Azam trophy he made 843 runs for National Bank of Pakistan at an average of 70. That form resulted in him being included in the Test squad for the ongoing tour of the Caribbean, after which Misbah-ul-Haq and Younis Khan will retire.
Fawad Alam averages 56 in first-class cricket and his non-selection in Pakistan's Test squad has been a mystery over the years. No selector has offered a satisfactory explanation.
Alam made his Test debut in 2009, when he was 24, and made 168 in his first Test at P Sara Oval. His performances were less impressive in the next Test at the SSC, and then four months later in Dunedin, and he's been on the outside ever since.
Seven years later, Alam is still a contender to fill one of the gaps left by Misbah and Younis' retirements. He's fit, has been making runs in domestic cricket, and his extensive first-class experience could make him the easy answer for the selectors.
Azhar Ali and Umar Amin made their Test debuts against Australia at Lord's in 2010, but their careers have taken divergent paths since then. Azhar's gone on to play 59 Tests and counting, while Amin's tally has stalled at four - 99 runs at an average of 12.
Amin never returned to the Test side but was in the limited-over squads periodically - 15 ODIs and 10 T20Is - and featured in the Pakistan A team. He was often praised for his agility, work ethic and utility as a bowler, but his prospects were hindered by injuries.
He now has 6589 runs at an average of 39 in 104 first-class games with a highest score of 281. Amin, 27, probably isn't an immediate contender for a Test spot but could push his case by performing consistently in domestic cricket.
Like Younis, Fakhar Zaman was also born in Mardan, a city in the Pakhtunkhwa province of Pakistan. He's made a strong impression in the last year: second highest run-scorer in the 2016 Pakistan Cup, prolific on the A tour of Zimbabwe, made 170 in the Quaid-e-Azam final, and was one of the successes of the 2017 PSL.
Zaman, 27, played the three T20Is on the ongoing tour of the West Indies - arguably he was picked for the wrong format - and has also been included in Pakistan's Champions Trophy squad. Having had success in first-class cricket, Zaman has a strong case for Test selection too.