Jens - CC filters are rarely used anymore with respect to color film. But warming and cooling filters relative to exposure color temperature, as well as UV filters, are still valuable, indeed essential if you want Ektar to behave. Once crossover occurs, it's very difficult to post-correct. If people tell you they can correct "anything" in PS, that's like an alleged chef telling you he can salvage any dish using a microwave oven a week later; but the taste simply won't be the same.
For Ektar I always have along a 2B Skylight filter for minor corrections, and either a KR1.5 or 81A amber warming filter for bluish overcast conditions. Correcting deep blue shadows under an open blue sky, especially at high altitude, requires even stronger warming, like an 81C. Split lighting, with part of the scene in deep blue shade, and some under open sun, is a more complex problem requiring a longer answer.
Porta films generally do not need the same kind of corrective warming filtration because it's kinda built-in. But that comes with the penalty of less neutrality of color. And I personally dislike the pinkish-orangish exaggerated Caucasian skintones of amateur color neg films like Kodak Gold. Portra 400 isn't quite as bad, but the effect is still there. But with all of them, green reproduction suffers as a result, and so too does decent differentiation between yellows, gold, oranges, warm tans,etc - those tend to get dumped right into the same generic bucket of "skintones". Ektar is distinctly better in that respect, but has its own problem with getting blue and cyan confused.