public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc();
    services.AddDistributedMemoryCache();
    services.AddSession(options =>
    {
        options.IdleTimeout = TimeSpan.FromSeconds(1 * 60);
    });
}

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    app.UseSession();
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
        app.UseBrowserLink();
    }
    else
    {
        app.UseExceptionHandler("/Home/Error");
    }

    app.UseStaticFiles();

    app.UseMvc(routes =>
    {
        routes.MapRoute(
            name: "default",
            template: "{controller=Home}/{action=Index}/{id?}");
    });
}

public class HomeController : Controller
{
    string ss = "dasdas";
    public IActionResult Index()
    {
        if (HttpContext.Session.GetString(ss) == null)
        {
            HttpContext.Session.SetString(ss, "Added into Redis");
            ViewData["ewq"] = "Empty";
        }
        else
        {
            string s = HttpContext.Session.GetString(ss);
            ViewData["ewq"] = s;
        }
        return View();
    }

    public IActionResult About()
    {
        ViewData["Message"] = "Your application description page.";

        string s = HttpContext.Session.GetString(ss);
        ViewData["das"] = s;

        return View();
    }
}