CTLA4 and neoplasm: Aberrant expression of B7-H4 in tumors mediates anti-CTLA-4 and anti-PD-1 resistance via different mechanisms, implying the synergistic efficacy of combination therapy with anti-B7-H4 and anti-PD-1/anti-CTLA-4 in overcoming B7-H4–mediated drug resistance and inhibiting tumor growth [96,114], which has been demonstrated in other tumors.