CliService.cs

using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace Mastersign.Playground.Hosted.Cli
{
    public class CliService : IHostedService
    {
        private ILogger Log { get; }
        private IHostApplicationLifetime Lifetime { get; }

        public CliService(
            ILogger<CliService> log,
            IHostApplicationLifetime lifetime)
        {
            Log = log;
            Lifetime = lifetime;
        }

        public Task StartAsync(CancellationToken cancellationToken)
        {
            Log.LogInformation("CLI Service started");
            Lifetime.StopApplication();
            return Task.CompletedTask;
        }

        public Task StopAsync(CancellationToken cancellationToken)
        {
            Log.LogInformation("CLI Service stopping");
            return Task.CompletedTask;
        }
    }
}

Mastersign.Playground.Hosted.Cli.csproj

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net5.0</TargetFramework>
    <OutputType>Exe</OutputType>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.Extensions.Hosting" Version="5.0.0" />
    <PackageReference Include="Serilog.Extensions.Hosting" Version="3.1.0" />
    <PackageReference Include="Serilog.Sinks.Console" Version="3.1.1" />
  </ItemGroup>

</Project>

Program.cs

using System;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Serilog;

namespace Mastersign.Playground.Hosted.Cli
{
    public static class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine($"Starting Generic Host...");

            var logTemplate =
                "{Timestamp:MMdd HH:mm:ss} [{Level:u3}] {SourceContext}{NewLine}" +
                "                    {Message:lj}{NewLine}{Exception}";

            Log.Logger = new LoggerConfiguration()
            .MinimumLevel.Verbose()
            .MinimumLevel.Override("Microsoft", Serilog.Events.LogEventLevel.Debug)
            .Enrich.FromLogContext()
            .WriteTo.Console(outputTemplate: logTemplate)
            .CreateLogger();

            CreateHostBuilder(args).Build().Run();
        }

        static IHostBuilder CreateHostBuilder(string[] args)
        {
            return Host.CreateDefaultBuilder(args)
                .ConfigureServices((hostContext, services) =>
                {
                    services.AddHostedService<CliService>();
                })
                .UseSerilog();
        }
    }
}