.NET Core Web API - Returning IActionResult from Actions

ValuesController.cs

[Route("api/[controller]")]
[ApiController]
public class ValuesController : ControllerBase
{
    [HttpPut("{id}")]
    public IActionResult Put([FromRoute] int id, [FromBody] SubjectSummary summary)
    {
        if(!Exists(id)) 
        {
            // NotFound() method returns 404 status code
            // NotFoundResult is returned from here.
            return NotFound();
        }
        
        // Not possible to return specific type
        // return summary;
        
        // Ok() method returns OkResult (200OK Status)
        return Ok(new { id = id, summary = summary });
    }
}