Laser powder bed fusion (LPBF) technology provides a novel processing route for the design and preparation of medium/high-entropy alloys (M/HEAs). The unique rapid solidification and repeated thermal cycling characteristics of LPBF endow the metallic material with a cellular structure featuring both elemental segregation and high-density dislocations. This cellular structure influences the deformation behavior of the metallic material and ultimately affects its mechanical properties, making tailoring the performance of additively manufactured materials key. Compared with conventionally processed M/HEAs, the cellular structure of LPBF affects dislocation behavior and can trigger additional deformation mechanisms, resulting in high strength-ductility synergy. Therefore, systematically reviewing the influence mechanism of the LPBF cellular structure on deformation behavior is highly important for improving the performance control theories of additively manufactured metallic materials and promoting their engineering applications.