CD274 and pneumonitis: It is unlikely that different clones of PD-1+ CD8+ T cells might have mediated antitumor effect and/or irAE (pneumonitis here) [12], although we could not entirely rule out the expression of PD-L1 on normal lung epithelial cells and other immune regulators in the tumor microenvironment (TME) due to the small size of available tissue specimen obtained by transbronchial fine-needle aspiration.