CTLA4 and breast cancer: Given that there was no definitive information available in the TCGA BC dataset for evaluating ICI treatment, samples were sorted into 4 IPS groups (CTLA-4_neg_PD-1_neg, CTLA-4_pos_PD-1_neg, CTLA-4_neg_PD-1_pos, and CTLA-4_pos_PD-1_pos) to reflect the sensitivity of BC patients to anti-PD-1 and anti-CTLA-4 therapy.