In this study, with data from a large prospective population-based cohort, we examined the relationship between pre-diagnostic obesity, measured as several anthropometric factors, and CRC risk according to the density of tumor-infiltrating immune cells of the T lineage (CD8+ and FoxP3+ cells) and B lineage (CD20+ cells), as well as PD-L1 expression on immune cells and tumor cells. This evidence concerns the gene FOXP3 and obesity due to melanocortin 4 receptor deficiency.