Real Madrid have been rather quiet in the transfer market for the last two years and have not made any signings apart from the arrival of David Alaba this summer.The 13-time Champions League winners did not perform up to expectations last summer and haven't been able to replicate the same success they had a few years ago. This could force them to venture into the market for new signings.Real Madrid need new signings to challenge on all frontsWhile Sergio Ramos and Raphael Varane left Real Madrid for PSG and Manchester United respectively, other players like Karim Benzema, Luka Modric and Toni Kroos are in their 30's. Understandably, they will soon need to be replaced with new signings if Los Blancos are to challenge on all fronts in the coming years.On that note, here are five signings that could make Real Madrid unstoppable in the future:#5 Eduardo CamavingaCamavinga could be an excellent addition to Real MadridWith the likes of Toni Kroos and Luka Modric in the twilight of their careers, it makes sense for Real Madrid to target Rennes midfielder Eduardo Camavinga.The Frenchman is widely regarded as one of the most promising young players plying their trade in Europe at the moment. Having broken into the first team at Rennes aged 16, the 18-year-old sensation has gone from strength to strength, already making 81 appearances for the Ligue 1 outfit.Real Madrid will be on red alert https://t.co/ngIZ1YJQHy— Football España (@footballespana_) August 7, 2021Camavinga's progress has enabled him to break into the French national team already, although he was not part of the squad that featured at UEFA Euro 2020 earlier this summer.The midfielder is currently in the final year of his contract and it has been reported that he has no intentions of signing a new one. It is believed that Camavinga has his heart set on a move to the Santiago Bernabeu instead.However, Real Madrid are expected to face stern competition to make him one of their new signings, with clubs like Manchester United and PSG also keeping tabs on him.#4 Harry KaneReal Madrid need a reliable goal-scorer for the futureWith Karim Benzema now aged 33, Real Madrid could look to make new and younger signings in the goalscoring department and Harry Kane could definitely fit the bill.Kane, who has scored 166 goals in 245 appearances for Tottenham, has been frustrated due to the club's failure to win and regularly compete for major trophies. As such, the Englishman is reportedly looking to seek an exit this summer.Amid heavy interest from Manchester City, Kane even reportedly refused to turn up to training last week, although he is now back and quarantining at the club's training ground hotel.🗣"I'm not surprised by a lot of it." Brad Friedel reacts to Harry Kane not turning up to Tottenham training this week and draws comparisons with Luka Modric's move to Real Madrid pic.twitter.com/FKGCS74Ief— Football Daily (@footballdaily) August 4, 2021It looks like Kane might stay at Tottenham this season and this could provide Real Madrid with a chance to make him one of their new signings.The 28-year-old fits the bill for Los Blancos and could seamlessly fill in Benzema's boots. However, it will still cost a hefty sum to lure him away next summer as the striker still has three years left on his contract.