HAVCR1 and cancer: While boosting T cells and NK cells function has primarily been the focus of tumour immunotherapy, the function of B cells, a crucial component of the immune system, in anti-tumour immunity remains a subject of debate.1 TIM-1, expressed on a subset of peripheral B cells, binds to phosphatidylserine exposed on apoptotic cells to promote tissue tolerance.1 However, its potential role in cancer has not been thoroughly investigated.