Likewise, the CD4+/PD-L1+ T cells were present more frequently in patients with endometriosis stages I and II (6.56 ± 3.44%, median 6.06%, Min–Max 0.97–11.51%) and stages III and IV (11.00 ± 6.72%, median 7.89%, Min–Max 3.58–22.79%) than in those from the control group (1.86 ± 0.70%, median 1.71%, Min–Max 0.98–3.49%) (Figure 2(d)). This evidence concerns the gene CD4 and endometriosis.