Widow was telegraphed. I didn't catch it until later, which I'll mention after:

#1 She jumped on board a liiiiiiiiiiiitle too quick for someone who is a spy and strategist.

#2 She featured heavily in the last Cap movie. She luh Cap.

#3 She showed up to his old girl's funeral just to give him a hug.

#4 She stays doing undercover shit.

#5 That part of the fight when she asks Hawkeye, "Are we still friends," and he says "it depends on how hard you hit me?" It was cute on its own, but then later when Wanda tells Hawkeye she noticed he was pulling his punches...and then Widow helps Cap?

Sure, it could still seem kinda iffy, right?

Until you wonder to yourself why the fuck Hawkeye came out of retirement to help Cap in this shit.

He didn't.

He came out because of his loyalty to Widow. She needed someone to pair off with in a big fight.