The existence of ${}^{12}C+{}^{16}O$ molecular resonances at sub-barrier energy has been a significant problem in nuclear astrophysics because they strongly affect the ${}^{12}C+{}^{16}O$ fusion reaction rate in type Ia supernovae and heavy stars. However, experimental surveys have been limited to 4 MeV and cannot access the deep sub-barrier energy due to a very small fusion cross section. Here we predict a couple of resonances with $J^{\pi }=0^{+}$, $2^{+}$, and $4^{+}$ in the deep sub-barrier energy based on the antisymmetrized molecular dynamics calculation that reproduces the known resonances and low-lying spectrum of ${}^{28}\mathrm{Si}$.