Our research findings strongly demonstrate that many immune properties against thyroid cancer exist in Treg, such as CD28‐ DN (CD4‐ CD8‐) %DN, CD3 on activated and secreting Treg, CD3 on CD28+ CD4+, CD28 on CD39+ CD4+, CD127 on CD45RA‐ CD4 not Treg and CD4 on secreting Treg. Here, CD4 is linked to thyroid cancer.