The MLS team announced the moves on Friday without disclosing contract details.
Sam had four goals and nine assists in 32 matches. The Englishman scored two game-winning goals and added three game-winning assists, including a 90th-minute winner against D.C. United on Sept. in a 1-0 win. Sam started all five playoff games for New York and had an assist.
Oyongo, who was on loan from Rainbow FC Bamenda, made 13 appearances, including 11 starts and recorded three assists in his first full season in MLS. The defender also appeared in all five playoff games and recorded one assist.