+1 on iZotope RX. Discovered it via SSD, and it's become the most reliably useful plugs I've ever invested in. Doesn't work absolute miracles - garbage in, garbage out - but it's still darned amazing.
Depending on the locations and scene, maybe also some ambient SFX in the background can be used to mask the remaining noise, once the worst of it has been removed without harming the dialog...but that depends entirely on the scene. The sounds of building machinery to underscore a tense scene will obviously not work for a tender outdoor moment. But maybe there's birdsong or insect sounds that could help to mask camera noise in a context like that. Just some examples to consider.
If signal:noise ratio is pear-shaped because the mic was too close to the camera relative to the talent, though, it may be ADR time.