  Despite significant experimental sensitivity to point-like, weakly
interacting particles at the electroweak mass scale, dark matter has not been
found yet. This could hint at a more complex dark sector with multiple states
or composite dark particles, much like the complexity of the standard model.
Currently, our experimental sensitivity to such scenarios is limited by a lack
of theoretical understanding. The investigation of Dark Matter systems with
unstable or stable bound states provides a playground that leads to the
development of important tools needed for the understanding of dark sectors
with complex phenomena and allows to experimentally test well-motivated DM
scenarios.
