C# Online Compiler | .NET Fiddle

using System;
using System.Collections.Generic;
using System.Linq;
					
public class Program
{
	public class Human
{
    public string FirstName{ get; set; }
    public string LastName{ get; set; }
    public List<Clothing> clothings { get; set; }
}

public class Clothing
{
    public string ClothingID{ get; set; }
    public string ColorTop{ get; set; }
    public string ColorPants{ get; set; }
}

public class CurrentClothes
{
    public string ColorTop{ get; set; }
    public string ColorPants{ get; set; }
}
	public static void Main()
	{
		Human h = new Human();
		h.clothings = new List<Clothing>();
		h.clothings.Add(new Clothing() { ColorTop = "Green", ColorPants = "A" });
		h.clothings.Add(new Clothing() { ColorTop = "Red", ColorPants = "B" });
		h.clothings.Add(new Clothing() { ColorTop = "Blue", ColorPants = "C" });
		h.clothings.Add(new Clothing() { ColorTop = "Brown", ColorPants = "D" });
		h.clothings.Add(new Clothing() { ColorTop = "Turqoise", ColorPants = "T" });
		
		List<CurrentClothes> currentClothes = new List<CurrentClothes>();
		currentClothes.Add(new CurrentClothes() { ColorTop = "Green", ColorPants = "A" });
		currentClothes.Add(new CurrentClothes() { ColorTop = "Turqoise", ColorPants = "T" });
		currentClothes.Add(new CurrentClothes() { ColorTop = "Red", ColorPants = "X" });
		
		var sameClothings = h.clothings.Where(x => currentClothes.Any(s => s.ColorPants == x.ColorPants && s.ColorTop == x.ColorTop)).ToList();
		foreach(var item in sameClothings) {
		    Console.WriteLine($"{item.ColorTop}-{item.ColorPants}");
		}
	}
}

 
using System;
using System.Collections.Generic;
using System.Linq;
                    
public class Program
{
    public class Human
{
    public string FirstName{ get; set; }
    public string LastName{ get; set; }
    public List<Clothing> clothings { get; set; }
}
​
public class Clothing
{
    public string ClothingID{ get; set; }
    public string ColorTop{ get; set; }
    public string ColorPants{ get; set; }
}
​
public class CurrentClothes
{
    public string ColorTop{ get; set; }
    public string ColorPants{ get; set; }

Cached Result

Environment version: .NET 9.0.0 (9.0.0), Unix 6.8.0.1014
Newtonsoft.Json version: Newtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed

Re-serialized MyApiResponseClass:
{
  "custom_attributes": [
    {
      "attribute_code": "required_options",
      "value": "simple"
    },
    {
      "attribute_code": "category_ids",
      "value": [
        "2"
      ]
    },
    {
      "attribute_code": "has_options",
      "value": "0"
    },
    {
      "attribute_code": "an_object",
      "value": {
        "0": "1"
      }
    }
  ]
}