Could you tell me what's the chances of kidney cancer coming in your kidney but only this time in both?

Rare: Bilateral kidney cancers at the same time are rare, perhaps ~2% of the time. Though this rate increases with certain genetic disorders.

Sometimes: Sometimes kidney tumors can occur in both kidneys. Often the second tumor is not related to the first (not recurrence or metastasis). In some cases, this is a random occurrence (called "sporadic"); however, sometimes multiple kidney tumors can be the result of an inherited (family) condition. Having long-term medical kidney disease can also predispose patients to develop more than one kidney tumor.