TNFRSF9 and neoplasm: Since T cells with different cell states could not uniformly respond to activation but rather exhibit a heterogeneous expression profile of activation markers and production profile of effector molecules [17, 18], isolating tumour-reactive TCRs based on the mRNA level of a single activation molecule (IFNG or TNFRSF9) through single-cell sequencing could result in the absence of tumour-reactive T cells.