To fill the void left by one of the greatest player to ever play the game is tough. Real did feel the lack of Ronaldo's presence for almost 3 years. In these 3 years, the one player who they have regularly backed upon is Karim Benzema.
The stats speak for themselves. Benzema has been providing almost 30 goals/assist for the third year running now and with injuries of Hazard and Asencio, the burden on his shoulders has only increased. The front 3 of Real has been subject to change almost every match and the one constant player has been Karim. He is the 4th all time highest goal scorer in the Champions Leagues only behind greats like Cristiano, Messi and Lewandowski.
He has also been instrumental in helping budding talent like Vinicius Jr and Rodrigo. Having an experienced campaigner like Benzema in the squad must be really helping them bring out their A game. Sure Cristiano was instrumental in the Champions League success' that Madrid has come to witness in the past decade, with a goal machine like him and Bale on the right Benzema played the perfect role for these to go their job with the one-two's and quick counter attacks.
His national career might not look like something of a striker of his caliber but that is due to differences between the National Team's couch and him. At the age of 33, he looks like he will be around for a couple more years shouldering Real and providing those necessary goal contributions.
It is time this man gets the credit he deserves. Undoubtedly one the Madrid legends and that's already an achievement in itself as the number of players to have worn that white shirt is huge.