  6G will likely be the first generation of mobile communication that will
feature tight integration of localization and sensing with communication
functionalities. Among several worldwide initiatives, the Hexa-X flagship
project stands out as it brings together 25 key players from adjacent
industries and academia, and has among its explicit goals to research
fundamentally new radio access technologies and high-resolution localization
and sensing. Such features will not only enable novel use cases requiring
extreme localization performance, but also provide a means to support and
improve communication functionalities. This paper provides an overview of the
Hexa-X vision alongside the envisioned use cases. To close the required
performance gap of these use cases with respect to 5G, several technical
enablers will be discussed, together with the associated research challenges
for the coming years.
