  A combination of four searches for new physics involving signatures with at
least one photon and large missing transverse momentum, motivated by
generalized models of gauge-mediated supersymmetry (SUSY) breaking, is
presented. All searches make use of proton-proton collision data at $\sqrt{s}
=$ 13 TeV, which were recorded with the CMS detector at the LHC in 2016, and
correspond to an integrated luminosity of 35.9 fb$^{-1}$. Signatures with at
least one photon and large missing transverse momentum are categorized into
events with two isolated photons, events with a lepton and a photon, events
with additional jets, and events with at least one high-energy photon. No
excess of events is observed beyond expectations from standard model processes,
and limits are set in the context of gauge-mediated SUSY. Compared to the
individual searches, the combination extends the sensitivity to gauge-mediated
SUSY in both electroweak and strong production scenarios by up to 100 GeV in
neutralino and chargino masses, and yields the first CMS result combining
various SUSY searches in events with photons at $\sqrt{s} =$ 13 TeV.
