It depends on your withdrawals. Blockfi is also a crypto lender.
The IRS treats sales or exchanges of cryptocurrency as a capital transaction.
Taking a loan would not be a taxable exchange, just like money received for a car loan is not taxable because you have pay it back with interest.
Rewards are generally not capital transactions because you have to do something to earn a reward. Most likely it will be hobby income because earning rewards is not a business for you.
And as tax guru @Critter-3 so expertly pointed out, interest is taxable as interest income, and is not a capital transaction.
For more info see TurboTax's Your Crypto Tax Guide.
