PDCD1 and nasopharyngeal carcinoma: Combining TCR repertoire and transcriptome analyses for each T cell, we revealed, for the first time to our knowledge, the differentiation trajectory of CD8+ T cells in NPC, by which CX3CR1+CD8+ T cells (CD8_C5_CX3CR1) in the peripheral blood infiltrated and transformed to the exhausted CD8+ T cells (CD8_C11_PDCD1) in tumours.