Add more than one append in http header

I am making an interceptor that should add in my header a token and an authorization whenever the value of authToken is different from null. My problem is in how to add an append in my header.

I tried something like:

@Injectable()
export class AuthInterceptor implements HttpInterceptor {

  constructor() {}

  intercept(req: HttpRequest<any>, next: HttpHandler) {
    const authToken = localStorage.getItem('token');
    if(authToken != null){
        const newRequest = req.clone({
            setHeaders: { Authorization: 'bearer ${authToken}' }
        });
        return next.handle(newRequest);
    }else{
        const newRequest = req.clone({});
        return next.handle(newRequest);
    }
  }

}