  We review arguably the simplest solution for the Hubble tension -- the
possibility that we live in a void. In this scenario, the local Hubble constant
$H_0$ is higher than the global value, thus potentially explaining why $H_0$
measured locally by the distance ladder including Type Ia supernovae (SNIa)
would be larger than the value inferred from the cosmic microwave background
and other cosmological probes. In addition, since the local supernova sample is
sparse and highly inhomogeneous, the error bars in the local Hubble constant
might be larger than previously estimated. These two effects -- local matter
density and sample inhomogeneity -- constitute the sample variance (or the
cosmic variance) of the local Hubble constant measurements. To investigate
these effects explicitly, we have mocked up SNIa observations by exactly
matching their actual spatial distribution in a large N-body simulation. We
have then investigated whether the sample variance is large enough to explain
the Hubble tension. The answer is resoundingly negative: the typical local
variation in $H_0$ is far smaller than what would be required to explain the
Hubble tension; the latter would require a 20-$\sigma$ deviation from the
expected sample variance. Equivalently, the void required to explain the Hubble
tension would need to be so empty ($\delta\approx-0.8$ on a scale 120
$h^{-1}{\rm Mpc}$) that it would be incompatible with the large-scale structure
in a $\Lambda$CDM universe. Therefore, the possibility that we live in a void
does not come close to explaining the Hubble tension.
