Hydration needs can vary from person to person based on body composition, treatment, activity levels, side effects, and much more. Sweating, fevers, diarrhea or vomiting increase hydration needs.
A baseline of 64-80 fluid ounces is usually recommended and this can come from beverages such as water, sports drinks, juice, milk, protein drinks, etc.
Also consider foods that have high water content such as soups/broths, fruits, vegetables, smoothies etc.