Mongodb – Getting Empty Object during Put request to the server

I created an API for following and followers user for Social Media Application, while request from postman getting empty object: {} But it seems to me to be correct.

Model:

const mongoose = require("mongoose");

const UserSchema = mongoose.Schema({
  username: {
    type: String,
    required: true,
  },
  password: {
    type: String,
    required: true,
  },
  firstname: {
    type: String,
    required: true,
  },
  lastname: {
    type: String,
    required: true,
  },
  isAdmin: {
    type: Boolean,
    default: false,
  },
  profilePicture: String,
  coverPicture: String,
  about: String,
  livesin: String,
  workAt: String,
  relationship: String,
  followers: [],
  following: []
},{
    timestamps:true
}
);

const UserModel = mongoose.model("Users", UserSchema);

module.exports = UserModel;

UserControler:

const UserModel = require("../Models/Usermodel");
const bcrypt = require("bcryptjs");

const followUser = async (req, res) => {
  const id = req.params.id.trim();
  const { currentUserId } = req.body;

  if (currentUserId === id) {
    res.status(403).send("Action forbiden");
  } else {
    try {
      const followUser = await UserModel.findById(id);
      const followingUser = await UserModel.findById(currentUserId);

      if (!followUser.followers.includes(currentUserId)) {

        await followUser.updateOne({ $push: { followers: currentUserId } });
        await followingUser.updateOne({ $push: { following: id } });
        res.status(200).send({message:"User Followed"});
      } else {
        res.status(403).send("User alredy followed by you!");
      }
    } catch (error) {
      res.status(500).send(error);
    }
  }
};

module.exports = { getUser, updateUser, userDelete, followUser };

UserRoute:

const express = require("express");
const {getUser,updateUser, userDelete, followUser} = require("../Controller/userControler");

const router = express.Router()

router.get("/:id",getUser)
router.put("/:id",updateUser)
router.delete("/:id", userDelete)
router.put("/:id/follow", followUser)

module.exports=router;

index.js:

app.use("/user",UserRoute)

Here is the complete details regarding the error, let me know what happens in the code, thank you.