combinate.java

    Retrofit repo = new Retrofit.Builder()
                .baseUrl("https://api.themoviedb.org/3/genre/")
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                .build();

        Observable<GenerosResponse> Genres  = repo
                .create(services.class)
                .getAllGeneros("movie","list","da0d692f7f62a1dc687580f79dc1e6a0")
                .subscribeOn(Schedulers.newThread())
                .observeOn(AndroidSchedulers.mainThread());

        Observable<ResponseMovies> Movies = repo
                .create(services.class)
                .getAllMovies(12,"movies","da0d692f7f62a1dc687580f79dc1e6a0","created_at.asc")
                .subscribeOn(Schedulers.newThread())
                .observeOn(AndroidSchedulers.mainThread());



        Observable<CollectionsMovies> combined = Observable.zip(Genres, Movies, new Func2<GenerosResponse, ResponseMovies, CollectionsMovies>() {
            @Override
            public CollectionsMovies call(GenerosResponse generosResponse, ResponseMovies responseMovies) {
                return new CollectionsMovies(generosResponse, responseMovies);
            }
        });


        combined.
                subscribeOn(Schedulers.newThread())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Subscriber<CollectionsMovies>() {
            @Override
            public void onCompleted() {
                Log.e("onCompleted:     ","finished");
            }

            @Override
            public void onError(Throwable e) {
                Log.e("onError:     ",e.getMessage());
            }

            @Override
            public void onNext(CollectionsMovies collectionsMovies) {


            }
        });