CTLA4 and neoplasm: Our current knowledge about CTLA4 and PD‐1 are mostly based on their functions in T cells.22 Although CTLA4 expression levels have been studied for the relevance of prognosis in NSCLC,12 and CTLA4 was found to be expressed in multiple tumours including NSCLC,12, 13, 23, 24 no further studies were done to reveal its function in tumour cells.