Composite image, replace background, etc

I am new to Capture One Pro 12 and am impressed with the powerful layer and masking features. It seems like it should be possible to add a feature that would allow a separate image to be imported into a layer of the image being edited enabling us to replace portrait backgrounds or landscape skies. Hope to see that feature added someday soon so I don't need to mess around with On1 Raw and Luminar. I'd rather just develop my skills in Capture One!