A protein called Meteorin-like (METRNL) in the tumor microenvironment saps energy from T cells, thereby severely limiting their ability to fight cancer, according to new research directed by investigators at the Johns Hopkins University School of Medicine and the Johns Hopkins Kimmel Cancer Center and its Bloomberg~Kimmel Institute for Cancer Immunotherapy. Finding ways to block the effects of METRNL signaling on tumor-infiltrating T cells may allow these immune cells to regain the energy necessary to eliminate tumors.