This is work in progress towards creating a theory unifying the standard model and gravitation, based on the idea of defining the theory on the Euclidean signature version of twistor space. Unlike other unification proposals, this does not introduce new, very different degrees of freedom, but just involves considering the Standard Model and a chiral formulation of gravity on the Euclidean twistor space. The new idea here is that the Euclidean theory has features not previously considered: one of the chiral SU(2) factors of the four-dimensional spin group can be taken to behave like an internal symmetry, and the breaking of this symmetry introduced by picking an imaginary time direction (necessary to define analytic continuation to physical Minkowski space-time) corresponds to the observed phenomenon of electroweak symmetry breaking.
For a very old embryonic version of this idea, see my 1988 Supersymmetric quantum mechanics, spinors and the Standard Model. A paper describing the proposal in more detail is available here. Blog posts about this are here and here. Slides from a September 2020 talk at OIST about this are here.