Crazy but true. Rock isn't really a genre at this time. You have indie...jam...prog stuff...mixes like Tame Impala...but not much I'd consider rock...
The biggest new(ish) group I can think of is King Gizzard and even they are allll over the map.
Some friends were discussing this months ago and we kept laughing at one suggestion it might still be Foo Fighters. After a long discussion of very few answers, we decided to google it...and yes the Ranker poll had at #1...Foo Fighters...a band from the 90s. There's truly no modern "rock n roll" as a popular music form.