  Using the density functional theory combined with dynamical mean-field
theory, we have performed systematic study of the electronic structure and its
band topology properties of Ce$_3$Pt$_3$Bi$_4$ and Ce$_3$Pd$_3$Bi$_4$. At high
temperatures ($\sim$290K), the electronic structures of both compounds resemble
the open-core 4$f$ density functional calculation results. For
Ce$_3$Pt$_3$Bi$_4$, clear hybridization gap can be observed below 72K, and its
coherent momentum-resolved spectral function below 18K exhibits an
topologically trivial indirect gap of $\sim$6 meV and resembles density
functional band structure with itinerant 4$f$ state. For Ce$_3$Pd$_3$Bi$_4$, no
clear hybridization gap can be observed down to 4K, and its momentum-resolved
spectral function resembles electron-doped open-core 4$f$ density functional
calculations. The band nodal points of Ce$_3$Pd$_3$Bi$_4$ at 4K are protected
by the gliding-mirror symmetry and form ring-like structure. Therefore, the
Ce$_3$Pt$_3$Bi$_4$ compound is topologically trivial Kondo insulator while the
Ce$_3$Pd$_3$Bi$_4$ compound is topological nodal-line semimetal.
