  We identify giant molecular clouds (GMCs) associated with HII regions for a
sample of 19 nearby galaxies using catalogs of GMCs and H regions released by
the PHANGS-ALMA and PHANGS-MUSE surveys, using the overlap of the CO and
H{\alpha} emission as the key criterion for physical association. We compare
the distributions of GMC and HII region properties for paired and non-paired
objects. We investigate correlations between GMC and HII region properties
among galaxies and across different galactic environments to determine whether
GMCs that are associated with HII regions have significantly distinct physical
properties to the parent GMC population. We identify trends between the
H{\alpha} luminosity of an HII region and the CO peak brightness and the
molecular mass of GMCs that we tentatively attribute to a direct physical
connection between the matched objects, and which arise independently of
underlying environmental variations of GMC and HII region properties within
galaxies. The study of the full sample nevertheless hides a large variability
galaxy by galaxy. Our results suggests that at the ~100 pc scales accessed by
the PHANGS-ALMA and PHANGS-MUSE data, pre-supernova feedback mechanisms in HII
regions have a subtle but measurable impact on the properties of the
surrounding molecular gas, as inferred from CO observations.
