PDCD1 and non-small cell lung carcinoma: The CTLA-4+ (HR = 1.336, 95% CI 0.636–2.808, P = 0.441, Fig. 6A) and PD-1+ (HR = 1.591, 95% CI 0.280–1.245, P = 0.162, Fig. 6B) lymphocyte infiltration in NSCLC brain metastases patients did not have a significant relationship with the OS.