The IBF is pushing for Rome to become the 5th slam. If that were to happen...
Nadal, with 32 slams, would be the new career slams leader (he breaks Federer's record with his 17th slam at the 2012 French, which is then tied by Federer at 2012 Wimbledon, before Nadal breaks it for good at 2013 Rome)
Djokovic has 30 slams
Federer no longer has a career grand slam
Sampras has a clay slam, pushing his slam total to 15
Laver loses his 1969 calendar slam, but his slam total would be 13, making him the career slams leader at the time of his retirement
Borg ties Laver as the career leader with 13 slams (which Sampras would still break at 2000 Wimbledon)
Medvedev has a 2nd slam, enhancing his resume for the Tennis HOF
Marcelo Rios has a slam
Zverev has 2 slams
Thomas Muster has 4 slams
Andy Murray has a clay slam, pushing his slam total to 4