There's currently no way to create native cutscenes as the game crashes when you try to make them using CodeWalker.
You can do the following if you want to create smooth camera movement:
1. Hide the hud every frame
2. Create 2 or more cameras
3. Use the native SET_CAM_ACTIVE_WITH_INTERP to transition between 2 cameras
As a bonus, here's a function I made to draw cinematic black bars:
public static void DrawBlackBars(float height)
{
NativeFunction.Natives.RESET_SCRIPT_GFX_ALIGN();
float y1 = 0.5f * height;
NativeFunction.Natives.DRAW_RECT(0.5f, y1, 1f, height, 0, 0, 0, 255);
float y2 = 1f - y1;
NativeFunction.Natives.DRAW_RECT(0.5f, y2, 1f, height, 0, 0, 0, 255);
}