Uniq -U Token4.txt > Finish.txt

uniq --help

Usage: uniq [OPTION]... [INPUT [OUTPUT]]
Discard all but one of successive identical lines from INPUT (or
standard input), writing to OUTPUT (or standard output).

Mandatory arguments to long options are mandatory for short options too.
  -c, --count           prefix lines by the number of occurrences
  -d, --repeated        only print duplicate lines
  -D, --all-repeated[=delimit-method] print all duplicate lines
                        delimit-method={none(default),prepend,separate}
                        Delimiting is done with blank lines.
  -f, --skip-fields=N   avoid comparing the first N fields
  -i, --ignore-case     ignore differences in case when comparing
  -s, --skip-chars=N    avoid comparing the first N characters
  -u, --unique          only print unique lines
  -w, --check-chars=N   compare no more than N characters in lines
      --help     display this help and exit
      --version  output version information and exit

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@echo off
setlocal enabledelayedexpansion
for /f %%_ in (a.txt) do (type "b.txt" | findstr /r "^%%_$" > nul 2>&1 && (for /f "tokens=*" %%# in ('type "b.txt" ^| findstr /r /i "^%%_$" ^| find /v /c ""') do (if %%# equ 1 (echo %%_ >> final.txt))))

C:\Users\leo\batch>type a.txt
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C:\Users\leo\batch>type b.txt
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C:\Users\leo\batch>code

C:\Users\leo\batch>type final.txt
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C:\Users\leo\batch>

C:\Users\leo\batch>type a.txt
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C:\Users\leo\batch>type a.txt | find /v "1" | find /v "4"
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C:\Users\leo\batch>