Color Grading replaces Split Tone in the latest version of Lightroom mobile for Android. Set the blending slider to 100 to achieve the same effect as the pre-existing Split Tone feature.
Tap Grading to adjust the colors of midtones, shadows, and highlights using the Color Grading sliders. There is also a Global slider with which you can adjust the overall colors in the photo without affecting the settings of midtones, shadows, and highlights. Furthermore, you can adjust the Luminance, Blending, and Balance of the colors for midtones, shadows, and highlights using their respective sliders.