TOX and neoplasm: Working with chimeric antigen receptors in knock out mice for the tox1 and tox2 genes, Seo et al. have shown that CAR-T deficient for tox1 and tox2 are more effective than wild type in suppressing tumour growth [33], whilst in a TCR transgenic adoptive transfer model, Khan and co-workers showed that heterozygous deletion of TOX1 in T-cells increases tumour growth control [31].