  Motivated by the recently discovered high $T_c$ nickelate superconductor
$\mathrm{La_3Ni_2O_7}$, we investigate superconductivity in a two dimensional
Hubbard model on square lattice that consists of two layers of hybridizing
$d_{x^2-y^2}$ and $d_{z^2}$ orbitals. Employing cluster dynamical mean-field
theory, we establish phase diagrams resolving the crucial dependence of
superconducting $T_c$ on electron hybridization $V$ between $d_{x^2-y^2}$ and
$d_{z^2}$ orbitals at the same layer, and on the hopping $t_{\perp}$ between
two $d_{z^2}$ orbitals at different layers. $V$ and $t_{\perp}$ are presumably
linked to the pairing phase coherence, and "pairing glue" of the system
respectively. Our result favors a two-component theory explanation of
superconductivity in a composite system. The influence of the pseudogap effect
and Hund's coupling on superconductivity are discussed, and also the
implication of our result to the understanding of $\mathrm{La_3Ni_2O_7}$
superconductivity.
