CD28 and metastasis: According to the Cox survival analysis of the four genes, the univariate survival analysis result showed that tumor stage (p < 0.001), tumor size (p < 0.001), lymph node metastasis (p < 0.001), distant metastasis (p = 0.002), as well as the expression of IL7R (p = 0.002), CD40LG (p = 0.001), CD28(p = 0.024), and HLA-DQB1(p = 0.014) all affected the prognosis of LUAD patients (Figure 4F).