CD274 and digestive system neuroendocrine neoplasm: Interestingly, CD8+ T cell infiltration was detected in the PD-L1-positive primary lung tumour nest, while it was limited to the stroma in the PD-L1-negative scapular metastasis, hence suggesting that the infiltrating CD8+ T cells in the tumour nest may play a key role in response to ICIs in advanced carcinoid tumours.