  A classical theorem due to Quillen (1969) identifies the unitary bordism ring
with the Lazard ring, which classifies the universal one-dimensional
commutative formal group law. We prove an equivariant generalization of this
result by identifying the homotopy theoretic $\mathbb{Z}/2$-equivariant unitary
bordism ring, introduced by tom Dieck (1970), with the
$\mathbb{Z}/2$-equivariant Lazard ring, introduced by Cole-Greenlees-Kriz
(2000). Our proof combines a computation of the homotopy theoretic
$\mathbb{Z}/2$-equivariant unitary bordism ring due to Strickland (2001) with a
detailed investigation of the $\mathbb{Z}/2$-equivariant Lazard ring.
