CTLA4 and neoplasm: Although it is too early to use FITC-YT-16 peptide as a strategy to treat tumors by blocking PD-1 pathway, it provides another example proving the concept that blocking PD-1/PD-L1 interactions by an antagonist peptide can enhance the anti-tumor activity of T cells, and this peptide may facilitate the evaluation of its combined use with an antagonist of other immune checkpoint molecules, such as CTLA-4, or even its use in combination with CAR-T cell strategy.