From version 5.7.3, Camera override properties have move to the new Render Overrides panel.
Render Overrides allow you to change some render properties per camera.
IMPORTANT: When using Overrides per camera, It is recommended to use a Main Camera and check its override property: it will define the fallback value in case Overrides are not enabled on other cameras.
Alternatively, consider enabling overrides for all the other cameras in your scene, or they will simply use the last settings that were applied and be affected by the rendering order of your cameras.
World Override: Overrides World for this camera. This allows you to assign different worlds for different cameras.
Frame Range Override: Overrides Frame Range for this camera. This allows you to render different parts of animation using different cameras.
Samples Override: Overrides Render Samples and Noise Threshold per camera.
Important: Cycles adaptive sampling is calculated using the pixel information pre-exposure. This means that Cameras with different exposures will require different Noise Threshold values to achieve the same level of noisiness.
Dicing Camera: Overrides the Dicing Camera used for Adaptive Subdivision. Leaving the property empty will use the current Scene Camera, but can create "crawling polygons" artifacts if the camera position is animated.
Film Transparent: Overrides the Film Transparent to render without the Background. This property takes priority over the Film Transparent Override value in the World Mixer panel.