Yes, the pension you inherited from your brother may be taxable.
You will receive a tax form when you make a withdrawal from the account. If you did not make a withdrawal during 2019 then you do not need to report anything on your tax return.
If you did make a withdrawal from the account during 2019 you should receive a tax form showing the amount of the withdrawal which then needs to be included on your tax return.
The tax forms are required to be in the mail by January 31, 2020 so you may not have received it yet.
More information about inherited IRAs or Pensions