CDK1 and neoplasm: The application of WEE1 inhibitors to tumor cells inhibits the activation of the G2/M cell cycle checkpoint, forcing tumor cells with unrepaired DNA damage to enter prematurely into mitosis, and promotes granzyme B-induced CDK1 phosphorylation, a dual effect that enhances the killing effect of cytotoxic T lymphocytes on antigen-positive tumor cells, causing a large number of tumor cells to die (Sun et al., 2018b; Friedman et al., 2018; Patel et al., 2019).