CTLA4 and non-small cell lung carcinoma: In order to understand whether CTLA4 is expressed in NSCLC, whether tumour cell‐intrinsic CTLA4 plays a role in tumorigenesis, we examined the CTLA4, PD‐1, PD‐L1 expression levels in multiple NSCLC cell lines with different oncogenic mutations and in the tissue samples from NSCLC patients.