Fresh findings in the search for long-lived heavy neutral leptons (HNLs) have been recently revealed by the CMS collaboration. These, also referred to as "sterile neutrinos," are fascinating theoretical particles that might answer three significant conundrums in particle physics: the possibility to account for the minute neutrino masses through the "see-saw" mechanism, the capacity to elucidate the matter-antimatter imbalance in the universe, and simultaneously offering a prospective candidate for dark matter.