Interestingly, this result is in line with a study by Correale et al. who found that a higher Foxp3+ T-lymphocyte tumour infiltration score is a favourable prognostic factor in colon cancer patients undergoing chemo- or chemoimmunotherapy.30 In accordance with other studies that report no change in the frequency of Treg cells in response to nivolumab or pembrolizumab, as reviewed in ref., 31 we found that the counts of FKBP51s Tregs were not significantly affected by anti-PD1, if not belatedly after at least 10 weeks from starting treatment. This evidence concerns the gene FOXP3 and malignant colon neoplasm.