Set the grill to medium-high. Husk the corn.
Grill 10 to 12 minutes, turning often, until charred in spots. Transfer to a cutting board and set aside to cool.
Cut the kernels off the cobb. Put the corn, scallions and cotija cheese in a medium salad bowl. Drizzle with the olive oil and toss.
Add the tajin (chili lime seasoning), cilantro and toss again. Taste for salt and pepper and adjust as needed.
Serve topped with more chili lime seasoning and fresh lime wedges if desired.
