<p>Borides, exhibiting complex bonding and structural diversity, are promising materials in the fields of ambient superconductivity and hard materials. Although some cage borides with either superhard or superconductivity have been reported, there is still a lack of systematic tuning of the metal centers in regulating their superconductivity and hardness. This study investigates the impact of s-block/d-block metal elements on the superconducting and hardness properties of boron cage lattices under ambient conditions. Using first-principles calculations, we predict a novel class of stable cage-like metallic borides, MB₈ (M = Na, Be, Mg, Sr, Sc, Y, Ti, Zr, Hf, V, Nb, Ta) characterized by metal embedded in B–B sublattices composed of 4/8 member B-rings. Superconductivity, hardness, and electronic structure calculations indicate that s-block and d-block metals influence the p-orbital occupancy of B bands, affecting both the electron-phonon coupling (EPC) constant and the bonding strength. In general, within the <i>I</i>422 MB₈ (B₁₆ cage) structural family investigated here at ambient pressure, s-block metals enhance the EPC constant (λ) and favour higher superconducting critical temperature (<i>T</i>_c) but weaken the hardness, whereas d-block metals contribute the opposite. Therefore, the <i>T</i>_c of NaB₈ reached 24.4 K, which is among the highest values reported for boron cage compounds, while ZrB₈ from d-block metals exhibits the highest hardness (21.9 GPa) among. This work proposes a pathway for designing novel superconductors with robust mechanical performance under ambient pressure and elucidates the distinct roles of s-block and d-block metals in modulating the superconductivity and hardness of cage-like borides.</p>