Understanding how electronic transport evolves from localized to itinerant regimes in correlated cluster solids remains an important challenge in condensed-matter physics. Here, we investigate the pressure-dependent transport properties of the lacunar spinel ${\mathrm{GaNb}}_4{\mathrm{Se}}_8$, a cluster Mott insulator at ambient conditions. At ambient pressure, the resistivity follows Efros-Shklovskii variable-range hopping, indicating Coulomb gap–controlled carrier localization. A pressure-induced electronic delocalization process begins at low pressures (∼5 GPa), as evidenced by the continuous suppression of room-temperature resistance. Upon further compression, the system undergoes a broad insulator-to-metal-like crossover in low-temperature transport, culminating in a fully metallic-like ground state at ∼17–18 GPa. In contrast, the crystallographic transition from the cubic phase to the monoclinic $C2$ phase starts at ∼20 GPa and ends near ∼32 GPa, demonstrating that the pressure-induced electronic evolution is completed before the onset of long-range structural symmetry breaking. At higher pressures, superconductivity (with a superconducting coherence length ξ(0) ≈ 80–90 Å) emerges from a pressure-induced metallic-like regime. These results establish ${\mathrm{GaNb}}_4{\mathrm{Se}}_8$ as a platform for studying correlation-driven evolution of electronic transport in cluster-based solids.

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• High-pressure studies
• Structural phase transition
• Superconductivity
• Strongly correlated systems
• Superconductors
• Density functional theory
• Electrical transport techniques
• Pressure techniques
• X-ray diffraction