  A statistical combination of searches is presented for massive resonances
decaying to WW, WZ, ZZ, WH, and ZH boson pairs in proton-proton collision data
collected by the CMS experiment at the LHC. The data are taken at
centre-of-mass energies of 8 and 13 TeV, corresponding to respective integrated
luminosities of 19.7 and up to 2.7 inverse femtobarns. The results are
interpreted in the context of heavy vector triplet and singlet models that
mimic properties of composite-Higgs models predicting W' and Z' bosons decaying
to WZ, WW, WH, and ZH bosons. A model with a bulk graviton that decays into WW
and ZZ is also considered. This is the first combined search for WW, WZ, WH,
and ZH resonances and yields lower limits on masses at 95% confidence level for
W' and Z' singlets at 2.3 TeV, and for a triplet at 2.4 TeV. The limits on the
production cross section of a narrow bulk graviton resonance with the curvature
scale of the warped extra dimension k = 0.5, in the mass range of 0.6 to 4.0
TeV, are the most stringent published to date.
