Glen Morgan returns as writer, and also as director, when Mulder and Scully go to Philadelphia to investigate murders related to a homeless relocation project.
Mulder is back, just in time to be buried, because nobody ever autopsies and enbalms an FBI agent who disappears for months and then turns up recently deceased.
Time travel stories are fun, but microbiology tells us they don't work like this. If you travel to the future, you die. If you travel to the past, everybody dies.