Both Galactic dust emission and Cosmic infrared background anisotropies (CIB) act as a dominant foreground contaminant for the measurements of the CMB anisotropies (intensity and polarization) at the frequency range above 217 GHz. The Galactic dust and CIB share a similar form of spectral energy distribution, which makes it harder to disentangle between them. An estimate of the CIB map acts as an external tracer of the CMB lensing potential, which would help detect the primordial scalar-to-tensor ratio [r] measurements through delensing. In our study, we apply the Bayesian inference technique to disentangle the dust and CIB emission using an external tracer of the dust emission. One of the primary outcomes of this study is to set the correct zero offset levels of the Planck intensity maps taking into account the pixel-dependent dust emissivities. We show that our determined offset values are compatible with the official Planck offset values up to 353 GHz and differ at frequencies above 545 GHz.