Depending on the pathogen you are facing, the previous advice may be spot on. But, if you have a soil-borne pathogen like Verticillium infecting the
roots and stems, then replacing the tomato plant may be the best option. Verticillium comes in species and within-species categories called vegetative compatibility groups. These are often rather host-specific at the level of plant family or thereabouts. Fusarium also has many species and plant-specific types. So, depending on what you've grown in that spot in previous years, you might be OK with almost any unrelated plant family. Maybe beans, chard, or some big crucifer?
Tests exist in many diagnostic labs to determine the pathogen species involved and even to determine its host plant affiliations. Those cost money of
course, and may take weeks to get results, but it might be worth it for planning future years' gardens.
On the other hand, some wilts are caused by non-specific bacteria. But, bacterial wilts are often slimy and icky, looking very different from fungal wilts.