  The neutrino sector offers one of the most sensitive probes of new physics
beyond the Standard Model of Particle Physics. The mechanism of neutrino mass
generation is still unknown. The observed suppression of neutrino masses hints
at a large scale, conceivably of the order of the scale of a Grand Unified
Theory (GUT), a unique feature of neutrinos that is not shared by the charged
fermions. The origin of neutrino masses and mixing is part of the outstanding
puzzle of fermion masses and mixings, which is not explained in the SM. Flavor
model building for both quark and lepton sectors is important in order to gain
a better understanding of the origin of the structure of mass hierarchy and
flavor mixing, which constitute the dominant fraction of the SM parameters.
Recent activities in neutrino flavor model building based on non-Abelian
discrete flavor symmetries and modular flavor symmetries have been shown to be
a promising direction to explore. The emerging models provide a framework that
has a significantly reduced number of undetermined parameters in the flavor
sector. Model building based on non-Abelian discrete flavor symmetries and
their modular variants enables the particle physics community to interpret the
current and anticipated upcoming data from neutrino experiments. Pursuit of
flavor model building based on such frameworks can also provide connections to
possible UV completions, in particular to string theory. We emphasize the
importance of constructing models in which the uncertainties of theoretical
predictions are smaller than, or at most compatible with, the error bars of
measurements in neutrino experiments.
