PDCD1 and lung adenocarcinoma: Jiang et al.[53] compared 12 paired samples of primary lung adenocarcinoma and BM and found a significantly immunosuppressive microenvironment in BM, with elevated CD8+ (p = 0.048) and CD4+Foxp3+ (p = 0.036) T cell infiltration, and programmed cell death protein 1 (PD‐1) expression (p = 0.047).