Okay, here in a scene in the new Season 4 episode 'Megaleech' that really stands out to me.

Adrien talks about how "we" can't let that happen, and then, watch this part.

He goes and grabs Marinette's hand!

Like if that isn't a clear sign of him liking her then I don't know what is.

Also, just a side note, but I've noticed that the animators/story writers are beginning to be a lot less subtle about hinting that Adrien likes Marinette (as is seen in the previous chapters I've done about Adrien liking Marinette).
I personally believe that this might be because Ladybug, his love, has began excluding him (as Chat Noir) in recent episodes and just not really respecting him as she should be, and so his feelings for her are possibly beginning to fade. But that's just my own take on this.