PDCD1 and breast cancer: As shown in Fig. 5 and Table 4, the expression of PD-1 was associated with favorable survival of breast cancer patients (HR = 0.67, 95% CI 0.49–0.91, P = 0.012) while PD-L1 did not demonstrate significant association with BC prognosis (HR = 0.85, 95% CI 0.62–1.17, P = 0.313).