In short, yes you can do this.
NOTE: Both the below approaches require some drivers to be installed on your server
Option 1: Direct access from SSRS
You could add a second datasource that points to your Excel file directly via an ODBC or OLEDB connection . You would then need to use lookups to effectively 'join' the data to your SQL data. There are several guides on how to use Excel data as an SSRS datasource out there.
Option 2: Access Excel data from t-SQL
However, my approach would be to do this on your SQL Server using OPENROWSET. This way you can access the data directly in your query and join it to your SQL data before you pass the results to your report.
Here's some a typical code snippet I would run to get Excel data into my database for further processing
SET @Cols = 'Country, Category, Period, Amount'
SET @Select = 'SELECT FROM [myExcelSheetName$A1:Z1000] '
SET @path = '\\myfileserver\myfolder\'
SET @filename = 'myExcelFile.xlsx'
SET @ExecCmd = 'INSERT INTO myExcelImportTable (' + @cols + ')
SELECT ' + @cols + '
FROM OPENROWSET(''Microsoft.ACE.OLEDB.12.0'', ''Excel 12.0;Database=' + @path + @filename + ';HDR=YES;IMEX=0'',''' + @select + ''')
WHERE Country != ''Country'' AND ISNULL(Country,'''') != '''' '
PRINT @ExecCmd
EXEC (@ExecCmd) AS LOGIN= 'myElevatedLoginName'
**Note: ** myElevatedLoginName is a SQL login that has admin level access. During testing/debugging I usually connect to my server with this login so you can run the t-sql commands directly.