CD4 and head and neck cancer: Furthermore, in various cancers including breast cancers, melanomas, colon cancers, prostate cancers, ovarian cancers and head and neck cancers 165-167, tumor-derived immunoglobulin-like transcript 4 (ILT4) and PD-L1 in EVs reprogrammed lipid metabolism and induced CD4+ T cell senescence via MAPK ERK1/2 signaling, leading to tumor progression and a poor prognosis 165, 168.