  The extragalactic distance scale is perhaps the most important application of
stellar distance indicators. Among these, classical Cepheids are high-accuracy
standard candles that support a $1.4\%$ measurement of Hubble's constant,
$H_0$. The accuracy of Cepheid distances is thus directly relevant for
understanding the implications of the Hubble tension, the $>5\sigma$ discord
among direct, late-Universe $H_0$ measurements and $H_0$ values inferred from
the early Universe observations assuming $\Lambda$CDM cosmology. This invited
review aims to provide an accessible overview of the state of the art distance
ladder that has established the Hubble tension, with a focus on Cepheids, their
absolute calibration using trigonometric parallaxes from the ESA mission Gaia,
and other Cepheid-related systematics. New observational facilities such as
JWST and upcoming large surveys will provide exciting avenues to further
improve distance estimates based on Cepheids.
