The study investigates the impact of the moiré superlattice in van der Waals (vdW) heterostructures on the optical properties of interlayer excitons. By stacking two monolayer semiconductors, lattice mismatch or rotational misalignment creates an in-plane moiré superlattice, which modulates the electronic band structure and can lead to novel transport properties. The authors present spectroscopic evidence that interlayer excitons are confined by the moiré potential in a high-quality MoSe$_2$/WSe$_2$ heterobilayer with a small rotational twist. They observe a series of interlayer exciton resonances with either positive or negative circularly polarized emission in photoluminescence, consistent with multiple exciton states confined within the moiré potential. The recombination dynamics and temperature dependence of these interlayer exciton resonances support this interpretation. These findings demonstrate the potential of engineering artificial excitonic crystals using vdW heterostructures for applications in nanophotonics and quantum information.The study investigates the impact of the moiré superlattice in van der Waals (vdW) heterostructures on the optical properties of interlayer excitons. By stacking two monolayer semiconductors, lattice mismatch or rotational misalignment creates an in-plane moiré superlattice, which modulates the electronic band structure and can lead to novel transport properties. The authors present spectroscopic evidence that interlayer excitons are confined by the moiré potential in a high-quality MoSe$_2$/WSe$_2$ heterobilayer with a small rotational twist. They observe a series of interlayer exciton resonances with either positive or negative circularly polarized emission in photoluminescence, consistent with multiple exciton states confined within the moiré potential. The recombination dynamics and temperature dependence of these interlayer exciton resonances support this interpretation. These findings demonstrate the potential of engineering artificial excitonic crystals using vdW heterostructures for applications in nanophotonics and quantum information.