I will discuss recent work in collaboration with Kevin Costello and Atul Sharma. Aspects of the holographic correspondence can be understood mathematically through a framework called twisted holography, which has been applied to AdS/CFT to compute certain protected correlators. In this talk we will apply these ideas to describe a new holographic duality for a bulk theory in an asymptotically flat spacetime which arises from studying twisted holography on twistor space. The ``boundary'' 2d chiral algebra, which is dual to the algebra of bulk asymptotic symmetries, can be described using a mathematical technique called Koszul duality. Alternatively, the 4d and 2d theories are independently defined from top-down string theoretic reasoning, and we match OPEs with collinear limits of scattering amplitudes in the planar limit as a check.