CD80 and neoplasm: Chemotherapeutics agents can elicit antitumor immunity in different ways: by inducing immunogenic cell death, resulting in neoantigens release in the TME; by upregulating the expression of tumor antigens themselves or of MHC-I and costimulatory molecules (B7-1 and B7-2) or by downregulating checkpoint molecules (PD-L1/B7-H1 or B7-H4) expressed on the tumor cell surface, thus enhancing the strength of effector T-cell activity.