Mr Marchionne, 66, had led FCA, which includes the Fiat, Chrysler, Jeep and Maserati brands, for 14 years, most notably through the impact and effects of the 2008 financial crisis, which threatened the existence of FCA and its big American rivals Ford and General Motors.
The boards of Fiat Chrysler, Ferrari and CNH Industrial have been called to meet in Italy in light of CEO Sergio Marchionne's surgery.
Camilleri is a Ferrari board member and the former boss of tobacco company Philip Morris, the main sponsor of the Ferrari Formula 1 team.
Manley also faces the test of meeting rigorous fuel-economy standards in Europe and China, along with managing through political uncertainty in Italy, and trade fears in the NAFTA zone and between the US and European Union - both important areas for Fiat Chrysler. According to FCA's statement, the company will continue with the 2018-2022 Business Plan that was implemented by Marchionne, which is aimed at doubling profits and investing heavily in electric vehicles.
The surgery was widely reported to be shoulder surgery about three weeks ago.
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Fiat Chrysler said in a statement that due to his health Marchionne "will be unable to return to work".
Marchionne had been set to retire in April 2019. Manley, 54, has been the head of the Jeep brand since 2009 and Ram since 2015. Elkann went on to describe Marchionne as a mentor, true friend and an "enlightened leader" with unusual intelligence.
This has also prompted succession plans at sportscar maker Ferrari and truck and tractor maker CNH Industrial, spun off from FCA in recent years. He created shareholder value for the Fiat-founding Agnelli family with successful spinoffs of Fiat's heavy vehicle maker CNH Industrial and of the iconic Ferrari super sports auto company. He was also a vocal and influential figure in F1 politics during his time as Ferrari's CEO.
FILE PHOTO: FCA CEO Sergio Marchionne attends the celebration of the production launch of the all-new 2017 Chrysler Pacifica minivan at the FCA Windsor Assembly plant in Windsor, Ontario, U.S. May 6, 2016.
Marchionne will also be remembered for his unapologetically blunt approach to both management and addressing the media, as well as his outspoken opinions regarding the automotive industry.