The recently reported $A{\mathrm{V}}_3{\mathrm{Sb}}_5$ ($A=\text{K}$, Rb, Cs) family of kagome metals are candidates for unconventional superconductivity and chiral charge density wave (CDW) order; both potentially arise from nested saddle points in their band structures close to the Fermi energy. Here, we use chemical substitution to introduce holes into ${\mathrm{CsV}}_3{\mathrm{Sb}}_5$ and unveil an unconventional coupling of the CDW and superconducting states. Specifically, we generate a phase diagram for ${\mathrm{CsV}}_3{\mathrm{Sb}}_{5-x}{\mathrm{Sn}}_x$ that illustrates the impact of hole doping the system and lifting the nearest van Hove singularity toward and above $E_F$. Superconductivity exhibits a nonmonotonic evolution with the introduction of holes, resulting in two “domes” peaked at 3.6 and 4.1 K and the rapid suppression of three-dimensional CDW order. The evolution of CDW and superconducting order is compared with the evolution of the electronic band structure of ${\mathrm{CsV}}_3{\mathrm{Sb}}_{5-x}{\mathrm{Sn}}_x$, where the complete suppression of superconductivity seemingly coincides with an electronlike band comprised of Sb $p_z$ orbitals pushed above $E_F$.

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• Charge density waves
• Kagome lattice
• Unconventional superconductors
• Density functional theory
• X-ray powder diffraction