  This letter presents the results from the MiniBooNE experiment within a full
"3+1" scenario where one sterile neutrino is introduced to the
three-active-neutrino picture. In addition to electron-neutrino appearance at
short-baselines, this scenario also allows for disappearance of the
muon-neutrino and electron-neutrino fluxes in the Booster Neutrino Beam, which
is shared by the MicroBooNE experiment. We present the 3+1 fit to the MiniBooNE
electron-(anti)neutrino and muon-(anti)neutrino data alone, and in combination
with MicroBooNE electron-neutrino data. The best-fit parameters of the combined
fit with the exclusive CCQE analysis (inclusive analysis) are $\Delta m^2 =
0.29 eV^2 (0.33 eV^2)$, $|U_{e4}|^2 = 0.016 (0.500)$, $|U_{\mu 4}|^2 = 0.500
(0.500)$, and $\sin^2(2\theta_{\mu e})=0.0316 (1.0)$. Comparing the
no-oscillation scenario to the 3+1 model, the data prefer the 3+1 model with a
$\Delta \chi^2/\text{dof} = 24.7 / 3 (17.3 / 3)$, a $4.3\sigma (3.4\sigma)$
preference assuming the asymptotic approximation given by Wilks' theorem.
