Here, we assessed the expression of PD-1 and CD39 in circulating memory (CD45RA-) conventional (Tconv; FOXP3-) CD4 T cells (Supplementary Figure S1) from head and neck squamous cell carcinoma (HNSCC) and cervical cancer (CC) patients and from healthy donors (HDs). Here, CD4 is linked to head and neck squamous cell carcinoma.