The phrase "promising candidate" refers to a person who shows great potential or likelihood of being successful and achieving positive results in a particular position or role. Full definition
The most promising candidate for a dark matter particle could be about to show itself at last, as it is running out of places to hide. (newscientist.com)
Interviews are held with the most promising candidates as needed. (themindtrust.org)
Their purpose is to further limit the list of promising candidates according to your strategy. (seekingalpha.com)