The Galactic dust emission and Cosmic infrared background anisotropies (CIB) dominate CMB at frequencies above 217 GHz. Galactic dust and CIB share a similar form of spectral energy distribution, making it harder to disentangle 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 the Galactic HI emission as 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. Our determined offset values are compatible with the official Planck offset values up to 353 GHz and differ significantly at 545 and 857 GHz frequency bands.