ONLINE COVER Unraveling tumor TRM signatures. The phenotype of resident memory T cells (TRM) differs between tissues, but how cancer affects the residence program of tumor-infiltrating T cells is unclear. Gavil et al. analyzed T cells from murine mammary fat pads and breast carcinoma tissue to identify defining characteristics of tumor TRM. Rather than adopting typical features of residence, breast tumor TRM acquired a signature distinct from healthy tissue including chronic antigen-driven exhaustion. This month’s cover shows an immunofluorescence image of T cells (cyan) expressing the TRM marker CD103 (magenta) within murine mammary ductal epithelium (green) after priming with vesicular stomatitis virus.