IL4 and neoplasm: These results suggest that upon receiving antigen restimulation (i.e., MC38 tumor rechallenge), Tcm likely differentiated into Tem and Trm where Tem secreted effectors such as IFN-γ and IL-4 for protective immune memory, while Trm emerged as a pivotal part of TILs staging immune surveillance and “safeguarding” the tumor microenvironment.