PDCD1 and lung cancer: To further study the relationship between COL1A1 and immunity, the coexpression between COL1A1 and the B7-CD28 ligand–receptor family was analyzed in lung cancer and normal lung tissues, including CD274, CD80, CD86, CD276, CD273, CD275, B7-H4, B7-H5, CD28, B7-H7, CD152, CD279, CD278, TLT-2 and NKp30 (Fig. 6A), based on TCGA dataset.