  Twisted holography relates the two-dimensional chiral algebra subsector of
$\mathcal{N}=4$ SYM to the B-model topological string theory on the deformed
conifold $SL(2,\mathbb{C})$. We review the relevant aspects of the duality and
its two generalizations: the correspondence between determinant operators and
"Giant Graviton" branes and the extension to non-conformal vacua of the chiral
algebra.
