In the present study, MYL5 expression negatively correlated with the markers of T cells exhaustion, such as PDCD1 (PD-1), CD274 (PD-L1), and CTLA4 (cytotoxic T-lymphocyte antigen 4), which indicated that MYL5 could play a positive role in prolonging survival prognosis for breast cancer patients. The gene discussed is CTLA4; the disease is breast carcinoma.