GZMK and infection: Specifically, granzyme A (GZMA), granzyme B (GZMB), granzyme K (GZMK) and perforin-1 (PRF1) [8,9,10,15] do not only induce apoptosis and modulate immune response within the tumor microenvironment (TME), but also have other diverse roles, such as potentially regulating homeostasis post-infection [11,16].