Van der Waals (vdW) bilayer assembled by two-dimensional (2D) layered materials, such as graphene, hBN and transition metal dichalcogenide (TMD), has become a fast evolving field for designing novel quantum materials. Many fascinating properties that have never been possessed by constituent monolayers have been reported, such as the famous unconventional superconductivity in twisted bilayer graphene, in which the flat band is formed at the magic angle due to electronic coupling. Specifically, the key control knob used to manipulate the vdW bilayer is through the stacking configuration, interlayer spacing and moiré pattern controlled by lattice mismatch and/or twist angle. In this talk, I will highlight recent advances in this field and discuss our work on tailoring the interlayer electronic coupling of valley excitons in vdW bilayers. By applying gigapascals high pressure, the greatly enhanced coupling strength further points to a new frontier in designing novel 2D electronic systems.