In ΛCDM, once local structures and survey systematics are carefully removed, the large-scale dipole in the galaxy distribution should be dominated by the same kinematic effect that produces the CMB dipole, with an amplitude and direction closely matching the CMB-inferred peculiar velocity in an otherwise statistically isotropic universe (Peebles 1993; Nadolny et al. 2021). However, wide-area radio and galaxy surveys often find galaxy or radio-source count dipoles that are significantly larger than the purely kinematic expectation, and in some cases only partially aligned with the CMB dipole, raising the possibility of an intrinsic large-scale matter dipole or unmodeled anisotropy that is difficult to reconcile with the standard cosmological principle in ΛCDM (Jain & Ralston 1999; Secrest et al. 2021).