CD8A and neoplasm: Prognostic analysis found that patients with EGFR mutations with high degree of CD3+ T cells, CD20+ B cell infiltration and larger numbers of TLS formation and high spatial distribution heterogeneity of CD8+ T cell had longer disease-free survival.<h4>Conclusions</h4>EGFR-mutated lung adenocarcinoma had a unique "non-inflammatory" tumor microenvironment with low infiltration of immune cells, and there was also heterogeneity in the tumor microenvironment among the tumors with different mutation subtypes and mutation abundance.