I'm not sure why you'd want to play Counter Strike 1.6 on Android but you can now
Dust out a classic
You could technically play Counter Strike 1.6 on Android before by mirroring or streaming the game from your PC but modder and developer Alibek Omarov has actually made a native version for Android complete with touch controls.
Granted, that's not how I'd want to play Valve's highly competitive FPS but it seems that you can plug a controller or better yet a mouse and keyboard with OTA cables.
It's an impressive feat for one coder and still a proof that highly moddable games can live on forever.
You'll need to follow this link to download the necessary APKs and complete these steps:
1) Install the APK. Install APK with omp postfix if you have multi-core device and noomp if you have single-core device or have problems with omp version.
2) Install the latest Xash3D Android from https://github.com/SDLash3D/xash3d-android-project/releases/latest.
3) Copy cstrike and valve folders from your Steam CS1.6 installation to xash folder on SDCard.
4) Run CS16Client!
[Source]