PDCD1 and neoplasm: They performed immune cell infiltration, intratumoral lymphocyte infiltration, stromal tumor-infiltrating lymphocytes, immunohistochemical staining (LAG-3, TIM-3, CTLA-4, and TUGIT), multiple immunofluorescence analyses (PD-1, PD-L1, and CD8) and gene analyses (RNA sequencing, TCR sequencing, and whole-exon sequencing), and an immune subclass analysis.