PDCD1 and breast cancer: The prognostic significance of PDCD1 (PD-1), PDCDLG1 (PD-L1), and PDCDLG2 (PD-L2) gene expression in primary BC was evaluated using the METABRIC dataset for OS and DSS (Figures S7A–C, S8A–C, S9A–C, and S10A–C in Supplementary Material).