There are 2 maximum levels in Cyberpunk 2077: Reputation has a maximum level of 50, which is the one you will normally reach first. This will unlock many gigs, all merchandise at vendors, as well as all options to purchase vehicles. You still have to go to the corresponding district for them to be offered to you. Reputation increases by completing missions, gigs and eliminating wanted targets, analyzing them, the reputation bonus appears in green.
Maximum level of V
The maximum conventional level is also 50. It will take you much longer to reach this limit, for example you will need to clean several districts of their secondary gigs and ongoing crimes. This limit implies that the total number of Attribute points is 71 (22 at character creation +49). You can therefore have 3 Attributes at the maximum threshold of 20. You will also get +49 Perk points by gaining levels, but this is far from being representative of the maximum amount of unlockable points, since the different Skills to do progress also gives it, not to mention the indeterminate number of Perk Shards hidden in the Night City map.