Multicolor immunophenotyping was used to determine the expression of PD‐1, TIM‐3, LAG3, CTLA‐4, CCR7, CD45RO, CD127, CD25, CXCR5, and ICOS molecules on CD3+CD4−CD56−CD8+ cytotoxic T cells freshly obtained from the lymph nodes and the peripheral blood samples of the breast cancer patients. The gene discussed is CTLA4; the disease is breast cancer.