Based on previous results from single-cell sequencing [8, 13, 14], we employed mIF to identify cytotoxic T cells (CD8+ cells), TRM cells (CD103+CD8+ cells), Tnon-RM cells (CD8+CD103− cells), immune checkpoints (PD-1, Tim-3), cytotoxic indicator (GZMB) and cancer cells (CK+ cells) (Fig. 1A). Here, PDCD1 is linked to cancer.