TOX and colorectal carcinoma: Moreover, immunofluorescence co‐localization analysis of patient‐derived CRC tumour sections revealed a significant spatial correlation (Pearson's r > .6) between TNFRSF18 and the canonical CD8+ T cell exhaustion marker TOX,43, 44, 45 exclusively within the tumour microenvironment (Figure 3F; Table S4; Figure S3C).