This　communication　describes　a　simple　sensitive　one-step　potentiometric　aptasensing　method　for　quantitative　detection　of　a　referenced　therapeutic　biomarker　(programmed　death-ligand　1,　PD-L1).　The　aptasensor　is　constructed　by　modifying　PD-L1-specific　aptamer　on　Ti3C2-MXene　nanosheets-functionalized　electrode.　Introduction　of　PD-L1　induces　the　specific　reaction　between　PD-L1　and　aptamer,　thereby　resulting　in　the　change　of　spatial　structures.　The　surface　electric　potential　of　modified　electrode　is　shifted　upon　addition　of　PD-L1　proteins　before　and　after　the　reaction　of　aptamer　with　the　analyte.　Interestingly,　potentiometric　aptamer　with　Ti3C2-MXene　nanosheets　can　achieve　a　higher　sensitivity　and　a　lower　detection　limit　toward　target　PD-L1　relative　to　aptamer-modified　electrode.　Experimental　results　indicated　that　the　linear　range　and　detection　limit　of　using　Ti3C2-MXene　nanosheets　were　0.01-100　ng　mL(-1)　and　7.8　pg　mL(-1)　PD-L1,　respectively.　Meanwhile,　the　specificity,　reproducibility,　storing　stability　and　accuracy　of　potentiometric　aptasensor　are　acceptable　for　the　screening　of　PD-L1　in　human　serum　samples.