Granzyme B (GZMB) is a cytosolic protease abundant in cytotoxic T-cells and natural killer cells, pivotal for immune defense. Delivered into target cells, GZMB activates caspase-independent pyroptosis by cleaving gasdermin-E (GSDME). This triggers pyroptosis, leading to target cell death. GZMB exhibits substrate specificity for aspartate residue cleavage and contributes to an activation cascade of caspases, impacting apoptosis execution. Involved in bacterial infection response, GZMB cleaves and activates caspase-7, promoting plasma membrane repair. Its multifaceted activities underscore its crucial role in immune responses and cellular defense.