CD28 and neoplasm: Along with TILs, is the expression of immune evasion molecules in the tumor microenvironment, including programmed death ligand-1 (PD-L1) and PD-L2 in tumor tissue and PD-1 (a cell membrane protein of the CD28 superfamily) on CD4+ and CD8+ TILs that have been demonstrated to influence the prognosis of TNBC [7–10].