Return newly generated cell value in MsgBox - excel

Question

Whenever I run this code, it generates a sequential number.
I want to display the new sequential number in a MsgBox, but it prints the older sequential number.
Private Sub ToggleButton1_Click()
Dim reponse As VbMsgBoxResult
Dim REVISIONRNCAUTO As Workbook
Dim Sheet2 As Worksheet
Dim cell_value As String
Set REVISIONRNCAUTO = ActiveWorkbook
Set Sheet2 = REVISIONCRNAUTO.Worksheets(2)
cell_value = Sheet2.Cells(4, "A").Value & Sheet2.Cells(4, "B").Value
If CheckBox1.Value = True And CheckBox4.Value = True And CheckBox7.Value = True And CheckBox2.Value = False And CheckBox3.Value = False _
And CheckBox6.Value = False And CheckBox5.Value = False And CheckBox8.Value = False And CheckBox9.Value = False And CheckBox10.Value = False And CheckBox11.Value = False And CheckBox12.Value = False _
And CheckBox13.Value = False And CheckBox14.Value = False And CheckBox15.Value = False Then
Sheet2.Activate
reponse = MsgBox("Êtes-vous sûr de vouloir générer ce RNC?", vbYesNo + vbQuestion, "Enregistrement RNC")
If reponse = vbYes Then
Sheets("Sheet2").Range("B4").Select
ActiveCell.EntireRow.Insert shift:=xlDown
Sheets("Sheet2").Range("B4:E4").Select
Selection.Borders.Weight = xlThin
Sheets("Sheet2").Range("B4").Select
ActiveCell.Value = "=b5+1"
Sheets("Sheet2").Range("A4").Select
Selection.Borders.Weight = xlThin
ActiveCell.Value = "E"
Else
Exit Sub
End If
End If
MsgBox ("Le nouveau RNC enregistré est le : " & cell_value)

Answer 1

You aren't changing the value of cell_value after you set it.
They are not linked forever like an Excel formula. You have to set it again once you change the cells that it is based on.
Put the cell_value = line right before the Else in addition to where it currently is.