  The era of atmospheric characterization of terrestrial exoplanets is just
around the corner. Modeling prior to observations is crucial in order to
predict the observational challenges and to prepare for the data
interpretation. This paper presents the report of the TRAPPIST Habitable
Atmosphere Intercomparison (THAI) workshop (14-16 September 2020). A review of
the climate models and parameterizations of the atmospheric processes on
terrestrial exoplanets, model advancements and limitations, as well as
direction for future model development was discussed. We hope that this report
will be used as a roadmap for future numerical simulations of exoplanet
atmospheres and maintaining strong connections to the astronomical community.
