Yes, the IRS will review your return in a year or two and check to see that you claimed all of the income earned in 2019, if they see you did not they will and add the income your return increase the tax and send you a letter advising that you did not claim all sources of income. The letter will show the changes including additional penalties and interest. You should file an amended return to add the income to your return as soon as possible to avoid penalties and interest.