Additionally noted by Dixon et al. [36] is the high expression of TIMD3 in ‘exhausted’ T-cells in cancers and chronic viral infections, although the associated upregulation of the expression of PD-1 (programmed cell death protein 1) was not observed in our patient cohort (p = 0.6 and q = 0.9, Supplementary File 1). Here, PDCD1 is linked to cancer.