UEFA rules provide for CAS appeal, the Premier League rules doesn't - it only provides for an independent commission appeal board for appealing guilty finding which Manchester City are currently doing and if the appeal board rejects City appeal, it'll be the final decision under the premier league rules. There isn't a CAS route in this one..
That is exactly what I stated

If City choose to challenge the punishment after failing at the guity finding appeal stage, they'd still refer them back to the PL independent appeal board and that wouldn't yield anything positive.
Manchester City cannot challenge or appeal the actual punishment with the independent commission. All they could have done was to appeal against the 115 charges with the commission and they have. Now they will have five days to make their appeal to the same independent commission asking them to reverse the decision.
After the independent commission announces their punishment, their participation in the matter is over. As per Premier League rules, Manchester City cannot appeal to the independent commission or to CAS. Their only option is to go to the High Court.
At least one sports channel has reported that the Premier League teams have privately agreed they will not accept Manchester City being relegated to the Championship because after one season they will win promotion back to the Premier League and they cannot accept giving a one season punishment when Manchester City have been cheating for over nine years. Also, it was reported that the Championship clubs have privately agreed that they will not accept Manchester City in their league.
Unless the Manchester City owners accept their guilt in order to minimise the punishment and then put the club for sale, their only option will be to fight the ruling. I expect Manchester City to appeal to the High Court against the punishment immediately but that will not stop many players and around
35 or more clubs lining up to sue Manchester City. I think their cases will be submitted to the High Court within days of the punishment being announced
if the independent commission did not award them compensation.