Can someone please check my code?

The compiler will help you find your mistakes, but some issues for your to ponder:

if (int player1guess = correctguess)    
         cout << "'player1' wins!";
   
   else if (int player2guess = correctguess)
      cout << "'player2' wins!";
    

   else if (player1guess , player2guess = correctguess)
      cout << "Its a tie";
   
   else if (player1guess != correctguess , player2guess != correctguess)
      cout << "You both lose :)";

line 1: if (int player1guess = correctguess)
You already initialized player1guess as int, don't do it again
a comparison should use ==
if (player1guess == correctguess)

and here:
else if (player1guess , player2guess = correctguess)
if player1guess is correct - you'll never get here, same goes for player2. So this will never execute.

And it's not proper C, it would not compiler. If you want to do this check - do it first.

if ((player1guess== correctguess) && (player2guess==correctguess))
    cout << "it's a tie";
else
if ((player1guess!= correctguess) && (player2guess!=correctguess))
    cout << "You both lose";

Keep at it, everyone starts at the same place. The main rule for programmers, ABC - Always Be Coding.
You get rusty quickly if you stop, and the learning never ends.

One trick to keep from falling for the '=' in comparison is to put the constant first:
if (42 = player1guess) would not compiler, but
if (player1guess = 42) would, although modern compilers would warn that you're probably doing something wrong here.