Acquire the depth map from the AR Foundation Occlusion Manager.

DepthImageVisualizer.cs

    void Update()
    {
        if (OcclusionManager.TryAcquireEnvironmentDepthCpuImage(out XRCpuImage image))
        {
            using (image)
            {
                // Use the texture.
                UpdateRawImage(_rawImage, image);
            }
        }
    }