  Over the last decade the gradient flow formalism has become an important tool
for lattice simulations of Quantum Chromodynamics. It offers remarkable
renormalization properties which pave the way for cross-fertilization between
perturbative and lattice calculations. In this contribution we report on the
construction of the flowed operator product expansion for the current-current
operators of the electroweak Hamiltonian at NNLO QCD. This allows for simpler
transformations between lattice and perturbative schemes and might reduce the
uncertainties of theoretical predictions for low-energy flavor observables.
