CD4 and infection: These migratory cDC (mDC) have been shown to drive and direct CD4+ and CD8+ T cell responses in homeostasis, infection and tumour settings (11–15), with both migratory cDC1 (mDC1) and migratory cDC2 (mDC2) being critical for the initiation of robust anti-viral and anti-tumour responses.