Pressure-induced superconductivity in ${\mathrm{FePSe}}_3$ was initially attributed to a spin-state transition, drawing parallels with magnetic fluctuation-mediated pairing in iron-based superconductors. This magnetic-centric view was later challenged by the discovery of superconductivity in nonmagnetic analogs such as ${\mathrm{SnPSe}}_3$ and ${\mathrm{HgPSe}}_3$, yet those cases were invariably accompanied by structural distortions, leaving the origin of superconductivity unresolved. Here, we report pressure-induced superconductivity in the nonmagnetic compound ${\mathrm{CdPSe}}_3$. No structural transition can be observed down to 80 K. Superconductivity emerges following a six-orders-of-magnitude decrease in electrical resistance, while the crystal symmetry remains unchanged. This observation raises the possibility that neither structural transitions nor magnetic ordering are required for superconductivity in this family. First-principles calculations support the experimental results and reveal an active role for chalcogen $p$ electrons in the superconducting mechanism. Our findings provide a unified understanding of the pressure-induced superconductivity in the $M\mathrm{P}{X}_3$ family and suggest that this material platform hosts a wealth of promising superconducting candidates.

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• High-pressure studies
• Pressure effects
• Structural phase transition
• Superconductivity
• Density functional calculations
• First-principles calculations