CD4 and neoplasm: Following activation by myeloid cells in tumour‐draining lymph nodes (dLNs), CD4+ and CD8+ T cells differentiate into various tumour‐infiltrating lymphocytes (TILs), encompassing T helper (Th1/Th2/Th17) cells, Tregs and Tfh cells (CD4+ CXCR5+ PD‐1high), among others.18