In addition:

“Yet Donald Trump’s letter firing FBI Director James Comey cited the advice of the former senator from Alabama as a reason for Comey’s termination.” 

“…news broke recently that Sessions’ meetings with Russian officials and subsequent statements to Congress may be grounds for perjury charges, according to senators Al Franken and Patrick Leahy.”

If there was no relationship between Sessions and Russia, he wouldn't have had to misinform Congress about it.