Yes, there is a way.
It's an app called UnityRemote 4 , here you can find all the information you can do so without generating the APK, if you want to use it on a physical device or emulator, if you want to use it in an emulator, just install this App and configure it as it is in Docs of Unity3d .
In summary, the steps that will need to be taken for the correct use of UnityRemote 4 are:
Install the UnityRemote4 App;
Connect your mobile device to your computer via USB (if you are an emulator, skip this step);
Put the mobile device in programmer mode;
Enter Unity3d and open the desired project;
Go to Edit > Project Settings > Editor;
Choose Device the option of Any Android Device or Any iOS Device (depending on the mobile device you want).
The other options within Editor Settings are not relevant but I recommend using them as is in this image:
AndroidAppDownload: Click Here .
App Download for iOS: Click Here