I have cancer, will there be complications with a salmonella infection?

Depends: It depends on the type of cancer, how widely spread, and how it has been treated (and responded). In general, if you have an intact immune system you should recover well from this with "supportive' treatment only (water, electrolytes, and food). If your immune system is suppressed or absent, there is some risk of prolonged illness and/or severe illness and should be treated with antibiotics.

Unlikely: Salmonella infections usually are due to food poisoning. If you have cancer and have very low blood counts (specifically, leukopenia) ask your doctor for a list of foods you should avoid. Adhering to this list will decrease your risk of infections, including salmonella.