I haven't come across any reports stating that Jake Tapper is penning a novel. His focus seems to be on his journalistic endeavors, such as reporting the news, conducting interviews, and providing analysis. However, it's not impossible for him to venture into novel - writing in the future, but for now, there's no indication of it.
If Jake Tapper were to write a novel, it might be about politics. Given his experience in covering political events as a journalist, he could create a fictional story set in the political arena, exploring power struggles, corruption, and the behind - the - scenes workings of government.
I'm not sure which is the very latest Jake Grafton novel as I haven't been updated recently. You could check at your local bookstore or on an online bookstore like Amazon.