CD274 and neoplasm: The failure of the biomarker's efficacy implies that relying solely on PD‐L1 expression levels as a selection criterion may result in some patients not benefiting from ICI therapy or incorrectly excluding those who could have benefited.[14, 15] Additionally, specific subsets of T cells within tumor tissues, known as tumor antigen‐specific T cells (TAST), have been shown in multiple studies to be predictive biomarkers of immunotherapy response.[16, 17] These T cells can recognize tumor antigens specifically, but not all have cytotoxic functions after antigen recognition.