Two dimensional (2D) materials have emerged as a fascinating field of research due to their unique properties that often differ significantly from their bulk counterparts. In the large familly of 2D materials, transition metal dichalcogenides (TMDs) ave garnered particular interest as they host a large variety of exotic electronic ground states such as superconductiviy, mott insulator and charge density wave (CDW). CDW is an electronic phase characterized by a spatial modulation of the electron density present in some metallic materials. While CDWs are well-understood in one-dimensional systems their origin in 2D materials remains less clear. The coupling between CDWs in heterostructures and their interactions with local perturbation is even more enigmatic. The primary goal of this internship is to shed light on the interactions between CDWs and their surrounding environment. We will investigate the coupling between two TMD materials exhibiting different CDWs and the coupling with atomic-scale defects, such as strong or weak pinning centers. To achieve this, we will use scanning tunneling microscopy and spectroscopy (STM/STS) to probe the electronic properties at the atomic scale in single-layer TMDs and TMD heterostructures.