The phrase "longstanding question" refers to a question or issue that has been around for a long time and has not yet been resolved or answered. Full definition
There have been longstanding questions about the impact of private tuition on exam results - and about the advantages gained by pupils whose parents can afford extra lessons. (bbc.co.uk)
While it's not entirely essential to have seen The Room before The Disaster Artist, it does elevate the experience, the script answering longstanding questions hardcore fans have had for years. (theguardian.com)
The report is the first independent, academic analysis to examine several longstanding questions that remain at the center of discussion over the cap and trade debate. (climateshiftproject.org)