“…Studies on regularity results for mixed local-nonlocal p-Laplacian type operators were initiated in the paper [36], where the De Giorgi-Nash-Moser theory was investigated by combining the techniques for the fractional p-Laplacian [28,29] with those for the classical p-Laplacian. We refer to [2,11,14,37,38,51] and references therein for further results concerning mixed local-nonlocal nonlinear problems. We would like to single out the paper [27] where maximal regularity, including (local) gradient Hölder regularity, was proved for a larger class of mixed problems related to −∆ p + (−∆ γ ) s with p, γ > 1 and s ∈ (0, 1) satisfying p > sγ.…”