Every separable Banach space is bi-Lipschitz isomorphic to a subset of $c_0$. But herethere are Banach spaces that do not uniformly embed in $c_0(\Gamma)$ for any $\Gamma$. See
- Jan Pelant, Petr Holický, Ondřej F. K. Kalenda, $C(K)$ spaces which cannot be uniformly embedded into $c_0(\Gamma)$, Fundamenta MathemematicaeMathematicae 192 (2006) pp. 245–254 (journal abstract page).