Selection Mask

In Photoshop CC, "Select and Mask" is a feature used to refine selections and create precise masks, often for cutting out subjects from backgrounds or isolating specific areas. It provides tools like the Quick Selection tool and Refine Edge to create more accurate selections.

Layer Mask

In Photoshop (PS CC), a layer mask allows you to selectively hide or reveal portions of a layer without deleting any pixels. It's a non-destructive way to control the visibility of a layer, offering flexibility and ease of editing compared to the eraser tool.