Both have experience in UCL, despite Milan's poor performance lately, but Real Madrid still have to work hard if they want to win, I'm sure Milan can put up a tough fight later at the Bernabeu but still if it's to be favored Real Madrid must be chosen.
My prediction is that Milan can score at least one goal because Madrid's defense is shaky, many important players cannot be fielded due to injuries, this opens up opportunities for Milan and of course they have observed this.
In my opinion the final score is 2-1 or maybe 3-1 for Real Madrid's victory.
Of course, Milan stands the chance to score since Real Madrid's defense is weak, Courtois hasn't fully recovered to play yet, while Lunin isn't performing as well as he did the previous season when he saved Real Madrid in a couple of matches when Courtois wasn't available. Real Madrid has an advantage when they play at home because they have more opportunities and, as we all know, they have greater motivation to defeat their opponents when they are playing in the presence of their fans. Real Madrid will undoubtedly win the match because Milan doesn't seem strong and has only won one of their past three Champions League games. They have been struggling to win their games since the start of the season.
Inter Milan vs Arsenal: Apart from expectations for Arsenal who are trying hard to compete with Manchester City in the Premier League, in terms of mentality in the Champions League, I think Inter Milan is more reliable.
I believe that if you see Inter Milan's last game against Young Boys, you are not going to consider them the favorite to win over Arsenal. Inter Milan struggled against a team that Barcelona humiliated with many goals, Inter Milan nearly lost the match, but victory was not in Young Boys' favor. However, both clubs won by a narrow goal in their last game; Marko missed a penalty in the 48th minute against Young Boys, and Trossard missed a penalty in the 78th minute of their previous Champions League game, so I'd rather go with both teams scoring.