In addition to Morten and dr bob's good words:
'Colour' filters (colour balance, colour correction) or 'B&W' filters (green, yellow, red etc 'contrast' filters) or both?
B&W filters:
First - if you are using B&W film there is no way a Photoshop filter can replicate the actual effect of a filter in front of the camera. That's simple.
If you are using colour film, and channel mixing , then you do have the possibility to choose which 'filter' to apply after the exposure. There will be a quality difference, and extreme filters like the deep reds especially won't be replicable, but there are many ways in which this method is a good one (heresy! burn her!).
Colour
With slide film: no contest, use filters on the camera.
With neg film: this is a much more equivocal issue in my mind. For absolute colour fidelity use camera filters. Otherwise overexpose and correct in Photoshop. I'll stop there in case this is not what you were asking about. Just ask if you want me to expand on these dangerously brief generalisations.
Best,
Helen