  We briefly discuss the most prominent results and specific sources detected
by gravitational-wave observatories LIGO-Virgo during first three O1-O3 runs,
as well as possible astrophysical and cosmological channels of their formation.
We show that it is possible to explain the observed correlation between the
effective spin of coalescing binary black holes and mass ratio of the
components by accretion from the ambient medium onto primordial binary black
holes. We also briefly discuss the recent results of searches for stochastic
gravitational-wave background in the nano-Hz frequency band by pulsar timing
arrays.
