Pressure Effect on All‐Inorganic Lead‐Free Halide Perovskite Materials: Structural and Optical Properties

All‐inorganic lead‐free halide perovskites have been at the forefront of state‐of‐the‐art optoelectronic materials due to their impressive optoelectronic properties and straightforward solution processability. The exceptional optical properties of halide perovskites are intrinsically linked to their structural characteristics, making the investigation of structure–property relationships critical for advancing functional material design and optimizing performance in optoelectronic applications. Among various tuning methods, pressure engineering is a highly powerful in situ technique, which can efficiently modulate the structural and optical properties. The pressure‐induced structural transitions of all‐inorganic lead‐free halide perovskite lead to significant bandgap engineering, piezochromic behaviors, and emission enhancements. However, systematic and comprehensive reviews in this field remain scarce. In this review, recent progress on studies on pressure effect on all‐inorganic lead‐free halide perovskite materials is summarized. The underlying mechanisms of pressure effects on these materials are discussed comprehensively. Finally, the current review challenges and offers insights into the future prospects for leveraging pressure effects to further develop perovskite structures and properties.