Cepheid variables in the Gaia Data Release 2 and the extragalactic distance scale

Classical Cepheids are the most important primary indicators for the extragalactic distance scale.
Establishing the precise zero points of their Period-Luminosity and Period-Wesenheit (PL/PW) relations
has profound consequences on the estimate of H0. Type II Cepheids are also important distance indicators and tracers of old stellar populations. The recent Data Release 2 (DR2) of the Gaia Spacecraft includes photometry and parallaxes for
thousands of classical and type II cepheids. Adopting a subsample of well studied objects, we use the Gaia parallaxes to derive new optical/Near Infra-Red PL/PW relations for the Galactic Cepheids. We use these information, coupled with proprietary data from the Vista Magellanic Cloud (VMC) survey, to discuss the zero point of the Gaia parallaxes and its impact on the extragalactic distance scale and the measurement of H0.