The recent discovery of superconductivity with T_c ~ 80 K in the bilayer nickelate La₃Ni₂O₇ under high pressure heralds a new class of high-T_c superconductors. The most notable feature of this material is a strong interlayer electronic coupling unlike many unconventional superconductors. In this respect, central questions concern “How does the interlayer coupling affect the low-energy physics?" and “Is the interlayer coupling a friend or foe of superconductivity?". In this talk, I will demonstrate using a cluster dynamical mean-field theory that nonlocal self-energy driven by the interlayer coupling in La₃Ni₂O₇ induces a Lifshitz transition of Fermi surface topology. By solving a relevant gap equation, I will further argue that superconductivity is promoted by this “dimer” electronic correlation. The underlying mechanism is the quenching of a strong ferromagnetic channel resulting from the Fermi surface change. This finding unveils the role of interlayer coupling in La₃Ni₂O₇ and potentially paves the way to designing higher-T_c nickelates.