Moir\'e trapped interlayer excitons (IXs) in heterobilayer transition metal
dichalcogenides currently attract strong interest due to their potential for
non-classical light generation, coherent spin-photon interfaces and exploring
novel correlated phases of electrons. Here, we report lasing of moir\'e trapped
IXs by integrating a pristine hBN-encapsulated MoSe2/WSe2 heterobilayer
in a high-Q (>104) nanophotonic cavity. We control the detuning between the
IX line and the cavity mode with a magnetic field and measure the dipolar
coupling strength to the cavity mode to be 78±4μeV, fully
consistent with the 82 μeV predicted by theory. The emission from
the cavity mode shows clear threshold-like behaviour. We observe a superlinear
power dependence accompanied by a narrowing of the linewidth as the distinct
features of lasing. The onset and prominence of these threshold-like behaviours
are significant at resonance whilst weak off-resonance. Our results show that a
lasing transition can be induced in interacting moir\'e trapped IXs with
macroscopic coherence extending over the lengthscale of the cavity mode. Such
systems raise interesting perspectives for low-power switching and synaptic
nanophotonic devices using 2D materials