CTLA4 and lung cancer: In lung cancer, patients have been observed to have greater T‐cell and Treg CTLA‐4 molecule surface density compared to intracellular density in healthy controls.31, 32 Further, studies have reported 40% of NSCLC patients to express CTLA‐4 on their tumor cells; notably increased CTLA‐4 expression in tumour tissue associated with improved survival, whereas in the TDLNs elevated CTLA‐4 expression correlated with poor prognosis.32 As such, therapeutically inhibiting the CTLA‐4 axis leads to increased activation of the immune system and is of clinical interest for the treatment of lung cancer.