  We review recent progress in the study of line defects in three-dimensional
Chern-Simons-matter superconformal field theories, notably the ABJM theory. The
first part is focused on kinematical defects supporting a topological sector of
the theory. After reviewing the construction of this sector, we concentrate on
the evaluation of topological correlators from the partition function of the
mass-deformed ABJM theory and provide evidence on the existence of a
topological quantum mechanics living on the line. In the second part, we
consider dynamical defects realized as latitude BPS Wilson loops for which an
exact evaluation is available in terms of a latitude Matrix Model. We discuss
the fundamental relation between these operators, the defect superconformal
field theory and bulk physical quantities like the Bremsstrahlung function.
This relation assigns a privileged role to BPS Wilson operators, which become
the meeting point for three exact approaches, localization, integrability and
conformal bootstrap.
