In situ cryo-electron tomography (cryo-ET) is a cutting-edge imaging technique that visualizes biological specimens in their native, near-native state at subnanometer resolution. By rapidly freezing samples to preserve cellular architecture (cryo-fixation) and capturing tilted 2D images under an electron microscope, cryo-ET computationally reconstructs 3D volumes of intact cells or organelles. This enables the study of macromolecular complexes, viral infections, and subcellular structures in situ, revealing spatial organization and dynamic interactions without purification or staining. Cryo-ET enables our lab to study viral-host interactions in situ at molecular levels inside the infected host cell.