For calibration on what could even be observed by the end of 2035: no intervention has made any mammal biologically immortal. The best-replicated drug effect is rapamycin in the NIA Interventions Testing Program, median lifespan up 23% in males and 26% in females at the highest dose (Miller et al. 2014), which is a slowdown with the mortality curve still rising with age. The only placebo-controlled lifespan trials of anti-aging drugs outside the lab are in dogs (TRIAD, funded through 2029, and Loyal's STAY study, up to four years from a 2025 enrolment close), so by 2035 the lifespan evidence in any animal that shares our environment will come from those. A human cohort enrolled at 65 reaches median survival about 21 years later. The arithmetic with sources (mine): https://w0lph.github.io/k9/why-dogs.html?v=2

Why the path to human longevity runs through dogs

Computed from the cited life tables and trials: a lifespan answer takes 4.6 years in dogs and 21 in people; dogs share our environment and diseases, lifespan has already been extended in dogs, and a regulator has accepted lifespan extension as an indication for dog drugs.