Spectrum sharing has been recognized as a key component for 5G and beyond wireless networks. Recent trials have revealed the business value of spectrum sharing via the licensed shared access model, wherein both the incumbent and the licensee operators are protected from harmful interference by sharing the available spectrum using long-term spectrum access agreements. Further increase in capacity gains can be achieved by exploiting dynamic spectrum access, where access is granted in shorter time intervals, and the Spectrum Access System, which is a more flexible version of traditional LSA. This article first hints at LSA-type spectrum sharing in regulatory and standards bodies, then proposes a few relevant scenarios that would take advantage of LSA, and finally presents an LSA system architecture and some enabling technologies for LSA/DSA/SAS. These include novel sensing, dynamic and radioaware resource allocation, and advanced cooperative communication techniques.