CD4 and cancer: Thus, while it is true that the overall immunophenotypic landscape of sepsis in the setting of cancer is characterized by increased expression of phenotypic markers of exhaustion, the CD4+ T cell compartment in these animals is heterogenous, with increased populations of both exhausted CD4+ T cells expressing PD-1 and activated CD4+ T cells exhibiting increased TNF secretion, both relative to non-cancer septic controls.