The IPS results showed that ips_ctla4_neg_pd1_pos, ips_ctla4_pos_pd1_neg, and ips_ctla4_pos_pd1_pos were significantly higher in cluster1 than in cluster2(P<0.05) (Fig. 4), suggesting that BC patients in cluster1 were more likely to benefit from ICI therapy targeting cytotoxic T lymphocyte-associated antigen 4 (CTLA4) and programmed cell death protein 1 (PD-1). This evidence concerns the gene PDCD1 and breast cancer.