CD274 and lung adenocarcinoma: (45), (2) origin of cell lines, A549 is a lung adenocarcinoma cell line with a mesenchymal signature and is known to be more resistant to the drugs targeting PI3K‐AKT pathway (46), and (3) the presence of intrinsic PD-1 protein expression in NSCLC cells that may inhibit tumor cell proliferation and might exert resistance to PD-1/PD-L1 blockades (47).