Younis Khan is the only Pakistan player to score over 10,000 runs in Test cricket while he has hit centuries in 11 countries.
Pakistan won the Test series against Australia after 20 years by winning the series 2-0 in November 2014 in the UAE.
The side's below-par performances in the recent past are likely the reason why he is resigning ahead of his contract.
Pakistan recovered from a terror attack in 2009 as they won the ICC World T20 by beating Sri Lanka in the final at Lord's.