Tunable van Hove Singularity without Structural Instability in Kagome Metal <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>CsTi</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>Bi</mml:mi></mml:mrow><mml:mrow><mml:mn>5</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

In Kagome metal CsV$_3$Sb$_5$, multiple intertwined orders are accompanied by both electronic and structural instabilities. These exotic have attracted much recent attention, but their origins remain elusive. The newly discovered CsTi$_3$Bi$_5$ is a Ti-based to parallel CsV$_3$Sb$_5$. Here, we report angle-resolved photoemission experiments first-principles calculations on pristine Cs-doped samples. Our results reveal that the van Hove singularity (vHS) in can be tuned large energy range without instability, different from As such, provides complementary platform disentangle investigate instability with tunable vHS metals.