  We formulate a pseudofermion functional renormalization group (PFFRG) scheme
to address frustrated quantum magnetism in three dimensions. In a scenario
where many numerical approaches fail due to sign problem or small system size,
three-dimensional (3D) PFFRG allows for a quantitative investigation of the
quantum spin problem and its observables. We illustrate 3D PFFRG for the simple
cubic $J_1$-$J_2$-$J_3$ quantum Heisenberg antiferromagnet, and benchmark it
against other approaches, if available.
