Preheat a grill to high heat.
Pat the rib-eye steak dry with paper towels.
Rub the steak lightly with olive oil and season generously with salt and pepper.
Place the steak on the hot grill and cook for 5–6 minutes per side for medium doneness, or longer to your preferred temperature.
At the same time, grill the corn, turning occasionally, until lightly charred and tender, about 8 minutes.
Transfer the steak to a platter, loosely cover with foil, and allow it to rest for 5–10 minutes.
Remove the corn from the grill and let it cool slightly before slicing the kernels from the cob.
In a small bowl, whisk together the olive oil, red wine vinegar, shallots, Dijon mustard, basil, salt, and pepper.
Place the spring mix in a large serving bowl and toss with half of the dressing.
Add the radishes, tomatoes, red onion, feta, and grilled corn.
Thinly slice the rested steak and add it to the salad.
Drizzle the remaining dressing over the top and gently toss.
Taste and adjust seasoning before serving this delicious Summer Steak Salad with Corn.