Although the abundance (i.e. density in cells/mm2) of most T‐cell subpopulations was significantly higher in 73 MSI (1,628 ± 1,687, MSI) compared to 1,039 MSS (1,028 ± 1,113, MSS) colorectal cancers (p < 0.05 each), the fraction of Type 1 (T‐bet+), Type 2 (GATA3+), Type 17 (RORγT+), regulatory (FOXP3+), and follicular (BCL6+) cytotoxic (CD3+CD8+) or helper (CD3+CD4+) T cells showed marked differences between MSI and MSS patients (Figure 2A,B and supplementary material, Figure S3). Here, CD4 is linked to colorectal cancer.